Now commonly available on new cell phones and some MP3 players, Bluetooth is a technology that basically replaces cables for connecting things to computers or other devices.
The most common use in cars is to enable hands-free phone calls without having to plug the phone into a headset. There's a one-time set-up required, but you don't even have to take the phone out of your pocket after that. Just get in the car and start the car. Your cell phone instantly becomes a fully integrated car phone.
But many Bluetooth-enabled cell phones are also MP3 players. Some products just hitting the market now enable the cell phone to become your in-car music library as well.
It's not only available on expensive luxury models. Ford's Sync system is available as an option on the 2008 Focus economy car. Besides the wireless Bluetooth connection, Sync also has ports for a USB connection or a simple audio cable connection.
Motorola says it will soon have a similar system available that can be easily added to a car after it's been bought. One of the devices won't even require installation and will simply clip to a car's sun visor, using an FM radio signal to send music to the car's stereo.
Also coming soon, some manufacturers could be offering systems that allow you to buy songs as you hear them on satellite radio stations, according to Hughes Telematics, the company that created the technology.
That way, you could fill your music library with brand new tunes as you drive.