Ultimately, I think a lot of people end up going to various game forums and posting requests for applicants. However I think that doing it this way leads to a lot of unqualified applicants and can waste a lot of your HR persons time sifting through them.
When my company started hiring game developers and modelers, they ended up going to several game conventions (GDC is the only one I can think of off hand) and setting up a booth. That way, you know the people there are more serious about wanting a job and not just replying on a forum. Also, the potential applicants know that your company is serious about hiring devs.