I love how my smiling, spooky tree turned out, thanks in large part to this tree bark tutorial on deviantart:
Here's another great art licensing resource: it's not free but it's a steal at just $2.99. It's Kate Harper's 20 Steps to Art Licensing, and it's another one of my favorite resources. It's a no-nonsense, straight to the point guide for breaking into art licensing. She literally lays out what you need to do in 20 concise steps. You really can't go wrong for $2.99. Kate also has a great blog with a list of companies that license art here.