Where can I find free copies of legal forms typically used by artists?

Not free, but for photographers, in any case, this is one of the best sources for that: http://www.amazon.com/Best-Business-Practices-Photographers-Second/dp/1435454294/ref=sr_1_1?ie=UTF8&s=books&qid=1258125256&sr=8-1

Along with lots of advice for running a successful photography business.

The biggest problem with finding something like that for free online is that it’s usually not been reviewed by a lawyer, which makes it suspect.

I’d also look around on nolo’s website: http://www.nolo.com/index.html

http://www.nolo.com/products/protect-your-artwork-RIP1C.html (including the consignment agreement, and model releases, for only $12, and this stuff is done by lawyers.).

Notably, for copyright: your work is copyrighted as soon as you make it, however you can only go after actual losses (not punitive damages) unless it’s registered. One good site to start with: http://www.uspto.gov/main/profiles/copyright.htm then:

http://www.copyright.gov/fls/fl115.html
and
http://www.copyright.gov/circs/circ40a.pdf

Adding a footnote to @grumpyfish‘s awesome advice above. If Orphan Works legislation passes we artists will lose implied copyright protection and the system will move into private hands. Also our ability for compensation if our work is used for profit without our permission will be greatly diminished.

Because of this it is vital that you not post any work on line without having a bold watermark with your name. You still should register with the government too for now but protect your work from easily being called “orphan” by using a visible watermark.