don't get an FM transmitter. unless you know of a radio station with 0 static... ever... don't get it. any static transfers over to the ipod. it's horrible for roadtrips, etc. seeing as how you'll spend more time searching for clear stations than you will actually listening to the dmn thing. if you're tring to save a few bucks, go with the tapedeck transmitter (if you have a tape player, of course). only about 18$, and the SQ's great compared to the FM transmitter. you just plug the ipod into a tape and play the tape. no static or anything. your best bet, though, is just a plain ipod adapter for a CD player. costs about 50$, but there are absolutely no disadvantages. period. no static, excellent SQ.
i went through this same problem about a month ago. ipod adapter ftw.
EDIT: oh yeah. and it charges the ipod while playing... like theothermike pointed out. get the adapter. you won't be disappointed.