I have a DLO TranspodFM. Friend had it and over the course of a trip, probably five hours total we were using the thing. Needless to say I liked it so I bought one for myself. I'm pretty sure I picked it up at best buy. A little pricey at 100$ when I picked up mine but so far it’s been worth it. Much better reception than the cheap FM powered battery transmitter I bought a radio shack. The best part about it is that while your driving it will charge your I pod so you wont run out of batteries in it...ever. You can also leave from somewhere with no charge and have it still work the whole trip because of its ability to charge the batteries.
Link:
http://www.bestbuy.com/site/olspage.jsp?skuId=7384332&type=product&id=1122654250706