I'm not sure if anyone has figured this out yet, but I have found a better way to listen to Pandora...
Instead of using the Pioneer PandoraLink app, I use the normal Pandora app. I do have the PandoraLink app downloaded and installed on my phone, I just never open it. I can have my phone plugged in, then start the Pandora app, and it will work normally...I do not have to unplug my phone and plug it back in like I had to do with PandoraLink. Sometimes, I do need to open the Pandora app 2 or 3 times to get the information on the AVIC screen, but it will keep playing music. When I do need to leave the app to do something else on my phone, Pandora keeps playing music...I do lose all the information on the screen, but it will come back once I re-open the Pandora app...Again, sometimes I do need to close and re-open the Pandora app a couple times on my phone to get the information and control back to the AVIC, but still A LOT better than the PandoraLink unplugging-replugging BS I had to go through.
I have an iPhone 3Gs with 4.0.2 software.