#1. Farhad, those things work with OTHER MP3 (and MP4, and whatever proprietary format iTunes uses) as well. "FM digital music transmitters" may be kludgy, but it's a little more honest. I use mine with my Zune.

#2. I bought cheapo ones on a 3 for $15 deal ($9.99 plus $5 shipping) on W00T. They work just fine, especially to play podcasts we both might want to listen to that we otherwise would have to burn to disc. They do NOT play music in super-high-quality. BTW, they also work better when you are going through zones with fewer/weaker radio stations--EXACTLY the kind of area where you might want to use them.

Just saying--they can be useful, but I'd wait and pick them up REALLY cheap.