Might be of interest. All time awesome paintovers by the people for the people er.. by the people!
Folks are adding more all the time.
If you have 10 minutes, give someone a hand them with their stuff in the Crit Forum, or if youre struggling with a piece, post it up there and folks will do their best to help.
And if someone gave you a good crit, show them some love and add it to the thread so everyone can benefit.