I just go off the phone with Apple and they made it sound like it's up to Pioneer to come up this a firmware up-date to address the problem.
My bet....they got the AVIC X920BT/X930BT Pandora app made by pioneer that is having issues with IOS5 with our older F900BT/F90BT/F700BT/X910BT/710BT units.
I'm likely getting a 4GS soon as part of our annual phone upgrade rotation. I'm thinking of taking advantage of the new mirroring feature of the 4GS when using the HDMI video cable. I will need an HDMI to composite converter, but those aren't too expensive. The advantage here is that no further IOS update will likely break anything and generally anything that can appear on the iPhone screen will show on the AVIC. I may use the AV2 input for this and hook up my old iPod Video to the AVIC IPod interface.