I need a FM transmitter that i can hook up to a cd player and broadcast it to several cars that are at least 30 feet away. Where would be the best place to shop for one of these and are there any suggestions? It needs to be able to use AC power and not have a car adapter on it.

Ummm... you planning a drive-in theater?

Here is a link to Ramsey Electronics. They have a number of transmitters and transmitter kits available. Price ranges from less than $50 to close to $300. You need to be aware of the restrictions involved as you are not allowed to interfere with any commercial stations. The Ramsey site details the restrictions pretty well.
http://www.ramseyelectronics.com/hk/default.asp?page=amfm
If you are not comfortable building the kit, they have some models available already assembled. Because of the restrictions on use, you won't find a lot of other manufacturers for this type of product.

..Doyle

Ummm... you planning a drive-in theater?

Haha! Well something kind of like that. My church has a drive-thru Easter drama and we want something to broadcast some instructions for the people coming to see the drama.