NYFA

One of the best online resources for artists has got to be NYFA.org (New York Foundation for the Arts). The website is a great tool for finding jobs - as all of the jobs are reviewed and filtered before being posted, so you don't have to rifle through hundreds of ridiculous postings before finding one decent one. Although it is pretty New York-centric, there are posts for all over the country, and occasionally something international.

NYFA is also a great place to look for calls for artists, residency opportunities, classes and workshops. Also, if you are looking for artist assistant, the pool of applicants you get from this site will be of really great quality. Go take a look at it and peruse the site - you'll find more than I can even talk about here.