Want an even more integrated solution? If your car has remote CD changer (so 5 years ago) or satellite radio with a long-dead subscription, Dice's Media Bridge makes kits tailored to fit specific Honda/Acura, Nissan/Infiniti, Toyota/Scion/Lexus, and BMW products dating back as far as '03 for most ('96 for some BMWs) that emulate your CDC or Sat radio, so they can be controlled by your stock head unit or steering-wheel controls.
Download the Livio Radio app to your smart phone, and you can stream 45,000 channels as if they were XM or Sirius channels, except they're all free. I bought a Dice unit for our '05 Acura TSX, and have been thoroughly impressed with the hands-free calling and music streaming. We leave an old iPhone plugged in as an iPod, and link the new one via Bluetooth for streaming Pandora or Tune-In Radio. There is also a 1/8-inch Aux jack for use with other devices. Toggling between Bluetooth, Aux, and USB is a bit fussy with our installation -- cycle the power off and on, then hit the channel-up button to advance from one to the next within 5 seconds. Little title/channel info is shared from Tune-In radio and channel changing must be done on the device, but music streamed from the smart phone via Bluetooth or USB gets artist/title info displayed and songs and folders can be navigated from the steering wheel. Not as perfectly integrated as a new OE system, but well worth the price. $299 plus installation ($75 for our TSX). www.diceelectronics.com