What I'm referring to is a site that works similarly to e-lance, rentacoder, etc, but is specifically aimed at free software projects.
Programmers are paid to implement a feature request, fix an error or build an application from scratch, and all code is licensed under the GPL.
It might also include collaborative/team features such as what's seen in SourceForge or Google Code.
For larger full-time projects, it might also include a job-board.