[mitchellwfox]

I second jaredtking on 99 Designs for logos and other work.

Elance (http://elance.com) is a good option generally for finding contractors.

While they are spendy, design-focused recruiters like Creative Circle and Creative Group can help you find both contractors and full-time employees. They do a decent job of screening so you only see qualified applicants, unlike Elance and 99 Designs.