As an amateur photographer, I find that photography forums are one of the best places to learn from more other photographers.  No matter what your level of experience, there is always someone there who can give you help and advice.

So my favourite photography forums are

1) Canon Digital Photography Forums

We especially like the fact that there are forums for showing samples from each lens.  So if you want to see what people take with each lens then check out the "Lens Sample Photo Archive".

2) Talk Photography Forums

Ok, I have only just joined Talk Photography, but the forums look really good, and I hope to get much more involved there.

3) The Photo Forum

This is another top photography forum full of tips and advice.  I think the forum sub categories are very good.  And it is very good for amateur photographers like myself for getting good advice.

4) Digital Photography Review

This is an excellent forum for discussing the kit you have.  For example, Canon 7D owners can jump straight in to the 7D / 5D - 10D forum.

Ok, the list isn't that long - but they probably are the most popular for many people.  What is your favourite forum, let me know in a comment.