Here are some of the websites:
The Painting Corps updates almost daily and links to a number of other sites.
The Painting Clinic is great for all the basics.
Terra Genesis is all about terrain...go figure.
This is a commercial page selling how to DVD's but still has some good tips.
Awesome Paint Job has a large number of useful videos and some good looking products.
Dakka Dakka has a huge collection of articles on many many topics.
Of course Cool Mini or Not is also a great site with a lot of articles.
And I forgot Massive Voodoo, which has a great blending article.
Well, that is about it, if anyone has any others please let me know and I will post.