Buy a desktop PC today and it's unlikely that you'll get a system with less than 80Gb of hard disk capacity. While this may sound like a lot of storage space, image files, music tracks, movie clips, system backups and software will quickly munch their way through it.

Saving files to CDs or DVDs will help free up hard disk space, as will investing in an additional internal or external hard disk, but another option is to take advantage of online storage to unclog your PC.

There are several online storage options, both free and paid-for. You may wish to opt for a dedicated online file storage service, but there is plenty of free web space available that can be used to store images and documents.

Most internet service providers (ISPs), for example, offer web space as part of internet access subscriptions, which could quite easily be used to create a website to show off photos to family and friends. Web-based email providers also now offer a generous amount of storage space for emails, which could be used to store documents as email attachments.

Online storage has the added advantage of allowing you to access the files you squirrel away on the web from just about any PC with an internet connection, which means you can access files when you're away from home. It's also particularly useful for backing up files in case the original becomes corrupted or is accidentally deleted.

Webmail
Let's start with the digital equivalent of sweeping dust under the carpet: webmail accounts. Storage is relatively cheap to buy and maintain, especially when you buy in bulk like ISPs and other online companies.

When Google announced on 2 April last year that it was going to provide an email service, the joke was on the likes of Hotmail and Yahoo, as Google's 1Gb of free storage eclipsed their puny offers, or at least it will when the service becomes available to all, probably later this year.

It was good news for consumers, though, as webmail providers scrambled to boost their services. Yahoo has announced plans for a free 1Gb from May, while Hotmail and Lycos now offer 250Mb and 300Mb, respectively, free.

Very few people will fill even 300Mb space with email correspondence, so why not email files to yourself as attachments and then transfer them to a dedicated folder in your inbox to keep them separate from regular emails?

Web space from an ISP
An alternative is to make use of the web space that most ISPs offer to users as part of their subscription package. Tiscali, for example, offers 100Mb of web space to all subscribers, while subscribers to the BT Yahoo Broadband package can use up to 15Mb of web space to create their own website and a further 100Mb for keeping large files online.

AOL does things slightly differently, offering 20Mb of online storage space per AOL Screen Name. As you can have up to seven screen names per account, you're looking at a total of 140Mb of storage.

As online storage space isn't a core part of an internet access service, it's likely that many of us won't have given it a second thought as a means of freeing up hard disk space or sharing files. It's a free resource, though, and one that gives you a good degree of flexibility over the way you want to use it, so it's worth exploring this as a storage option.

There are two main choices to be made before you get started, based on the way in which you wish to use this space: do you want to create a website to share photos and files with other people or do you simply want to use the space to back up large files on your PC?

Build your own
If you want to create your own website, you'll need some software to help you through the process. Mindscape's WebCreator is one of the cheapest at £20, and offers a range of templates around which to base your site. If you create a basic website without flashy animations, you should count on using up between 10 and 20Mb of your web space allowance just to store the actual site online.

Bear in mind that many ISPs impose restrictions on data transfer, which will limit the number of visitors you can have to the site each month. You'll also find that many ISPs won't let you store music files on a publicly-accessible website due to piracy fears. Understandably, ISPs want to distance themselves from the distribution of illegally copied music and if you are using an ISP's service you have to abide by its rules.

You'll also need a web address for your site and you may need FTP software to transfer the web page you create offline to your web hosting service. (See 'Moving large files' below for more on FTP.)

You can also use the free web space at your disposal to back up important files for your eyes only; it's certainly a cheaper alternative to the online storage services we mentioned. While we wouldn't recommend you use this to store the only copy of important files in existence, it's a handy way to back up copies of non-sensitive documents.

If you have grander designs for your online storage space, you could take advantage of free web hosting services such as those from Freewebsites.com or Freewebsitehosting.com to tailor-make your website to suit your needs.

You could even pay for the services of a web hosting company such as Easyspace or the website hosting services offered by Lycos. The most basic package on offer from Lycos (the Starter package) gives you 50Mb of web space for £2.50 per month, with charges starting at £2 per year for a domain name.

Online photo albums
Image files in particular tend to gobble up hard disk space and if you just want to find a new home for your digital snaps, there's no point doing all the legwork involved in getting a website up and running when online photo album services have already done most of the hard work for you.

Websites such as Kodak's EasyShare Gallery, Canon's Fotango and Photobox allow you to create online photo albums of digital snaps that others can view online. These three services offer unlimited storage space for your snaps, which is a real bonus.

You'll need to register with the website you choose to use before you start creating online photo albums but registration is free and pretty straightforward. It's then a question of creating a photo album with a date and title and uploading the images you want included to the site.

You can add notes to images and invite others to view the album by sending out a link to your photo album via email. All the photos you store on the site are password protected and you'll need to sign in to access your own photo albums so others can't view your images unless you invite them to.

Online storage services
Type 'online file storage' into Google or any other search engine, and websites such as Xdrive or iBackup offering dedicated online file storage are likely to feature prominently in the results returned.

These websites allow you to store copies of important files on their servers for a fixed monthly fee. As well as providing you with extra storage space above and beyond the capacity of your PC's hard disk, these services allow you to access data stored in your account when you're away from home.

Xdrive offers a 15-day free trial of its service, after which you'll have to part with $10 (about £6) a month or $100 (about £58) a year for a 5Gb storage allocation. There's also a 10Gb service, which costs $20 (£11) per month or $200 (£95) per year. iBackup offers an identical pricing plan for its economy storage packages.

Xdrive offers you the choice of uploading files and managing your rented storage space online or opting to have your rented storage space show up as available hard disk space on your PC.

If you opt for the second option you can drag and drop files and folders into your Xdrive storage space on your Desktop, just as you would when transferring files or folders to any other folder on your PC. You can also set the service to automatically back up the data on your computer every day, which is handy if you are working on a daily basis with important information.

Access to the data you store on Xdrive and other similar services is password-protected to keep it safe from prying eyes, but we would still recommend exercising caution when it comes to storing sensitive data online.

Here today ...
Be aware that storage services shouldn't be seen as an untouchable vault for your important data. Webmail accounts are a good bet, but look at the terms - Hotmail will delete accounts that aren't accessed for more than 30 days, for example.