Useful links:
http://www.thefreelibrary.com/How+to+Hire+A+Voice+over+Talent-a01073757448
http://www.articlesnatch.com/tag/voiceover+talent/
http://ezinearticles.com/?Voice-Over-Talent---Hire-A-Pro&id=857185
http://www.prlog.org/10010246-new-talent-for-voice-over-recordings-in-french.html
http://radioproduction.suite101.com/article.cfm/how_to_become_a_voice_over