For those looking to grab some free custom voiceovers without the cost, check out http://www.rhetorical.com/cgi-bin/demo.cgi
It’s a top online voice sythesiser which (depending on the voice option selected) can produce some pretty realistic stuff. The Amercian male and Australian female voice options are particularly good.
As a demo, here are a couple of IDs I’ve put together using voices from the site together with the help of some Soundforge effects…
http://www.tellytunes.com/jinglemad/tellytunes_synthvocuts.wav