If you're looking for a voice for your project, and the ethics of people you do business with matter at all, you should know that not all sites are created equal. There are several shady and misleading websites out there, some of them quite large, purporting to pair voice talent with those in search of voice talent, all the while looking to bilk both parties in the process.
Here are a couple of the good ones. These are honest people working to introduce voice-seekers to qualified talent, as transparently and fairly as possible.
If you're specifically looking for imaging talent, there's only one place to go, and that's HOSS.
These aren't the only voice over sites operated by decent people, but they're some of the ones with which I've been most impressed, from the agents to the talent they represent. I'm also always happy to recommend another voice talent if I'm not exactly the right fit for your project.