Voiceover greats Marc Cashman and Pat Fraley lend their insights on audiobook performance to a new article at Backstage.com. Highly recommended reading!

Getting an agent to represent your voiceover career requires the following: talent, persistence, professionalism, and at least the ability to gain the slightest understanding of what a Voiceover Demo is.
Then again, this is just my opinion. Maybe you don't really need any of those things. In fact, if you're bereft of all four items, I urge you to plow forward regardless with all haste and fervor! Oh, you certainly won't land an agent, but you'll provide bloggers like me with plenty of compelling material.
By way of example, the fine folks at Voice Over Xtra bring you an e-mail transcript of a recent exchange between VO agent Roger King of PN Agency and "an aspiring voice talent". I won't spoil it, but let's just say that the latter description is probably a bit generous.
Actress and author Deborah Puette gives an in-depth, first-hand look at taking the plunge into her first VO demo. Her work with producer/voice actor Ed Cunningham is also documented on video. Highly recommended!
(Courtesy of Backstage.com)
I recently updated my Imaging demo. This one's focused on radio; I'll have new ones dedicated to TV promos, trailers etc. later, but for now I wanted to focus on the "station voice" side of things.
Continued thanks to Frank Frederick for stepping in and editing the demo to a tight 52 seconds and sweetening it just a tad.
Have a listen, and --- assuming you approve --- feel free to bend the ear of any radio folks you may know. *ahem*