Today I purchased the VIP upgrade off the XBL Marketplace. I went to my garage on Forza 3, but could not find the cars contained in the VIP bundle. Is there a way to identify them on your cars list, or do I have to buy them in game as well. 
 
Also, I remember seeing on forzamotorsport.net that VIP members have been getting cars gifted to them by Turn 10 on a regular basis since the game's launch. Are these the cars included in the bundle, or do I miss out on these for not buying the Special Edition of the game? 
 
Thanks in advance for any help you guys can provide me with!

I'd give it a little time. I've heard Turn 10 does waves of gifting, checking to see who's new to the VIP program. When that time comes around, you should receive a slew of gift cars.  Unless they've changed their tune, anyone new to VIP still gets all the cars they missed gifted to them eventually. Gifted cars or cars purchased in auction will have a little globe and arrow logo above them in the My Cars menu to designate they were downloaded or gifted.
 
Until the gifts come flowing in, all that's readily available are the five VIP cars that were previously locked from purchase or use. Those are cars like the Corvette ZR1, the Ferrari 430 Scuderia, the Lambo Gallardo Superleggera, and a few others.

I got all the VIP cars gifted to me about a day after I downloaded the VIP upgrade. Thanks PsEG!