Since it's a topic that's been discussed several times (and it's related to a lot of posts), I thought I may post this here. NO!SPEC is a site/campaign about working on speculation an the consecuences of that practice. It includes lots of information on contests an the such. One of the latest entries is about some illustration contest, and its fine print.
I don't know, thought it may be useful, or at least informational.

http://www.no-spec.com

See ya.