Convert .m4b to mp3 or aac

[Erik Gilchrist]

I just downloaded the 9-11 Commission hearings off of iTMS (Free) and 
would like to be able to play them in my car. I have no iPod. I am on 
the road a lot and while I can't write (I write a lot) being in the car 
is the perfect place to listen.

My car can play MP3(on CD-r) but not the .m4b format if I toss it onto 
CD. Bummer.

Any ideas?  these are about 28 files all about 1.5 hrs in length so 
doing the normal workaround of burn to AIIF CD, then rip back to Mp3 is 
not ideal.

e