An multimedia device integration system is provided. One or more after-market audio or video devices, such as a CD player, CD changer, digital media device (e.g., MP3 player, MP4 player, WMV player, Apple iPod, portable media center, or other device) satellite receiver (e.g., XM or Sirius receiver), DAB receiver, video device (e.g., DVD player), cellular telephone, or any other device or combinations thereof, is integrated for use with an existing OEM or after-market car stereo or video system, wherein control commands can be issued at the car stereo or video system and data from the after-market device can be displayed on the car stereo or video system. Control commands generated at the car stereo or video system are received, processed, converted into a format recognizable by the after-market device, and dispatched to the after-market device for execution. Information from the after-market device is converted into a format recognizable by the car stereo or video system, and dispatched to the car stereo or video system for display thereon. One or more auxiliary input sources can be integrated with the car stereo or video system, and selected using the controls of the car stereo or video system. A docking station is provided for docking a portable audio or video device for integration with the car stereo or video system. Wireless integration between the portable audio or video device and a car stereo or video system is provided, and voice recognition and speech synthesis capabilities are provided in the portable audio or video device or the car stereo or video system.