If your car has a slot for tapes instead of CDs, you can buy a specially adapted cassette that connects to your iPod via a 3.5mm jack plug. This then allows you to play your favourite iPod music through your car's stereo.
Be warned, though - sound quality is poor. FM transmitters don't cost much more to buy, and can be used on any car stereo.
Cassette adaptorsiStuff Cassette Adaptor Best price we found - £2.99 (www.ipodworld.co.uk)
Belkin Mobile Cassette Adaptor Best price we found - £6.93 (Amazon.co.uk)
Commtel Car Cassette AdaptorBest price we found - £9.95 (Argos.co.uk)