I have the ipod plug in FM modulator but never use it as I wire straight into the autocom and don't bother using it in the car.
Ipod is great but the battery is crap I get between 1 & 2 hours from a full charge. My problem is I bought it about a year & half ago, started filing it with music and only started using it a couple of months ago so can't get it replaced under warranty.
There is no fix, you send the unit back, cough up $99 if in the US, still trying to find out how much it is here, and they send you a new or refurb unit.
I ldo like the look of the ipod photo though, but really want a player the size of the ipod but with a genuine 8-12 hour battery life or better yet removable batteries.