No doubt you will have heard someone at some point speaking of the internet as a source for great change or great good. And it is - although possibly not in the sense that many people mean.

The fact is that the web makes it easier than ever to support good causes, from allowing networks of volunteers around the world to communicate with each other more easily, to simply providing 'click-donating' where you can quickly make some sort of a difference. And even if it's a small donation, it's worth doing, so here's our guide to helping out.

All charities say that regular giving is the key, so here's a simple trick to get you started. Change your home page from your internet service provider (ISP) or daily newspaper to one that supports click-donating. Our favourite is the Hunger Site www.hungersite.com which promises to hand out food for every visitor that clicks on the 'Donate Free Food' button.

How does it work? Sponsorship. As the site says: "Your donation adds to over 200 metric tons of food donated weekly to the United Nations World Food Programme." When you click through, you'll be taken to a second page where you'll see adverts from that day's sponsors with an invitation to click onto their own websites.

You don't have to do this - and to be fair, it doesn't always seem appropriate to go off and visit a credit card site given the context - but they're the ones who make this method of giving possible.

If you don't get it, or think there's something strange going on, the Frequently Asked Questions page should allay your suspicions, and if you're sold on the idea, there are screensavers to download and you can stick a button on your own site.

Food for thought
You can also donate extra food or land by signing up for one of the free email newsletters, and they also provide a clever template which you can use to invite sign-ups from nominated friends and colleagues pointing out what the site does and why they should get involved.

The Hunger Site's also good because it has front page links to the Rainforest Site and the Kids Aids Site which both work in the same way. Make one of them your home page today. (You can only click-donate once a day on each site by the way, in case you're wondering).

If you feel like understanding this, and other, models of giving, then UK Fundraising, a kind of online magazine at www.fundraising.co.uk/index.html, is an excellent and wide-ranging resource. You'll find charity-related news, a discussion list, warnings of email hoaxes, ideas for raising money yourself and stacks of other stuff.

While you're there, make sure you check out www.fundraising.co.uk/examples/affinity/internet.html#paybar which has details of, and links to, many of the sites that run click-donate or similar schemes.

Some of these are surprising. A small group of ISPs will donate a proportion of the money they make from your web surfing (i.e. the phone charges) to charity. Some you will never have heard of and others, like www.waitrose.com, you would normally associate with comestibles rather than communications.

Which takes us neatly into the shopping option. The whole notion of having a proportion of the purchase price of a product going to a good cause not only satisfies our desire for fairness, but also makes us feel a bit better about our rampant consumerism.

Start at www.twogifts.co.uk where up to 18 per cent of your money will be donated to one of their sponsored charities - including Oxfam, Shelter and Amnesty International - and by clicking down the list of items on the left you'll find more than a few famous names like Dell Computers (www.dell.com), Books Online www.bol.com and the various Streets Online sites.

All in a good cause
Alternatively, with Christmas coming up, why not visit www.goodcauses.co.uk where there are details of more than 250 charity-related card shops in the UK. There's no online ordering, but you'll be pointed to a local shop and they reckon that the 81p in the pound donation made £4m last year, which is a lot of ho-ho-ho in anyone's book.

If you click the 'Member Charities' button on the left you'll be zipped through to a set of clickable links to sites run by a host of charities including Barnardo's, Mencap, Help The Aged, the NSPCC, The Samaritans, the RNIB and the Stroke Association. And don't forget that sites like QXL (www.qxl.com) regularly hold auctions for charitable causes. When we visited they had a signed poster of Gary Lineker. Moving swiftly on, then.

Often, the good causes seem too big for individuals to feel there's any point in trying to change anything. But the internet is excellent for bringing people together and allowing them to communicate freely, to set up group initiatives and thus help to individualise those big issues (which, by the way is at (www.bigissue.com).

The place to start is the Voluntary Service Overseas site at www.vso.org.uk where you can find out if you have the necessary skills and commitment to work abroad as a volunteer. They're currently looking for teachers, IT people, social and community workers, engineers and a range of other professionals.

At the Institute Of Cultural Affairs site (www.ica-uk.org.uk/index.htm#top) you can find out about their own distinctive volunteer programme, or go to Global Volunteers at www.globalvolunteers.org/ who do the same. You could also check out the Ireland-based Agency For Personal Service Overseas (www.apso.ie/indexhome.html) which offers some of the clearest guidelines of any site we've seen on what to expect.

By the way, the point in commending these is not to decry organisations like UNESCO, which is perhaps more recognised, but to offer suggestions of places to go when you want to help directly, rather than reading about what others are doing or how your donations can help.

A dog's life
If you don't fancy helping humans, then what about animals? There are lots of organisations beyond the RSPCA (www.rspca.co.uk) including Viva! (Vegetarians' International Voice for Animals) which campaigns for what it calls a "sane diet" and has the support of Sir Paul McCartney. They're at www.viva.org.uk.

This is also home to the world's first animal welfare game, The Cat's In The Bag - although presumably this involves neither a real cat nor a real bag.

If that sounds too radical, for between £30 and £1500 you could adopt one of the animals at either Dudley Zoo (www.dudleyzoo.org.uk/adopt.html) or Dublin Zoo (www.dublinzoo.ie/help_adoptions.htm), and there are always greyhounds waiting to be helped out at www.greyhoundrescue.co.uk.

The key is to be creative about the way you help. How about giving blood? Find out when your next local public session is by using the search facilities at www.blooddonor.org.uk, or go the whole hog and carry an organ donor card (uktssa.org.uk/d0.asp).

You could support The Prince's Trust (www.princes-trust.org) and volunteer for community work; join The Samaritans (www.samaritans.org); do yourself some good by getting the Inland Revenue to chip in to any overseas charitable contributions (www.giftaid2000.org.uk); or read the radical agenda of those who believe that it's the entire human race that needs help before we destroy the whole lot (www.jubilee2000.com). It's your planet. Look after it.