Connecting ipod to car stereo

[lucemma4]

I recently bought a new car with a standard car stereo in, Im looking to buy a cd player head unit that has an aux port so that I can plug my ipod into it. I've been looking on Halfords site and the port they have on their stereos is called a pre-out, Im not sure what that is! Also I've heard you can buy a device to go in your car that plays songs from your ipod through your stereo-its not an itrip i already have one of those. Im looking to spend up to �150 and would like a semi decent one thats a good make. Any help would be great, thanks.

[Alltorque]

More than one piece of kit out there, but Dension is worth a web search.