I've just found three interesting websites for illustrators:
Storybird is a collaborative storytelling site for people who want to make an illustrated book. It works like this. Illustrators can have a shop there with about 50 images, and site users can select from those illustrations, construct a story around them, and pay a small fee for the use of the images. From memory (as I can no longer find this information on the site) it's only about 25c per image used and the site managers take 30% commission, but once they're in the shop, the images can be re-used for many Storybirds by different site users. It's an interesting concept linking the illustrator directly to the 'consumer' (usually, kids). If anyone's had experience of this site as an illustrator, I'd be very interested to hear their views.
Artist Daily is the website of American Artist magazine and has an online forum for artists and various free pdfs etc you can download on art topics.
Watercolour Wednesdays, a collaborative blog where published or aspiring children's book illustrators can go to practise their art with weekly challenges, and share their art and methods. This week's challenge was to do a picture of children doing something they enjoy in spring, so this was mine.