Edge Studio is a great marketing resource for voice overs. They have a ton of great resources for voice over training, too!. Visit their answer series for common questions and answers if you’re intending on becoming a voice over artist. You might also find their directory for suggesting links particularly useful.
If you’re needing other voices, feel free to email me with your requirements. I’ll speak with people I know to be extremely talented, reliable and quick and will either get back to you myself or have them contact you directly (whichever you prefer).