The market for FM transmitters looks set to explode, with many companies bringing out a range of products that will allow consumers to wirelessly connect mp3 players to radios and in-car entertainment systems.

These products will save consumers money as they will no longer have to shell out to buy mp3-compatible stereos.

Both Kensington and Belkin have been quick to promote their digital FM transmitters compatible with the iPod, which will be legal to use in the UK from 8 December.

Kensington’s £50 Digital FM Transmitter/Auto Charger enables owners to play their tunes through the car stereo, over any available FM frequency while charging the device via a car’s DC power source. The FM transmitter has three programmable station presets and an up/down tuning button, allowing users to choose the FM frequency over which they wish to broadcast.

The Digital FM Transmitter uses digital wireless technology from Aerielle, which claims to enhance noise reduction and stereo separation by using the line-level audio signal from an iPod's dock connector port instead of the headphone jack.

Similarly, the Tunebase FM transmitter from Belkin plays iPod tunes through the car stereo as it powers and charges the device. It comes with tray adapters to fit various iPod models, including the new Nano.

Although transmitters that wirelessly connect mp3 players to radios and in-car entertainment systems have been available to buy in the UK for some time, they have been illegal to use, as according to the updated Wireless and Telegraphy Act of 1949, low power FM transmitters interfered with legitimate broadcasts.

The likely stampede in sales comes as a result of a new law passed last week, which now makes the use of FM transmitter’s in the UK legal. From 8 December the public will be allowed to use such devices, so long as they have the CE mark showing that they comply with the European standard set by ESTI and approved by Ofcom.

Although many of the transmitters coming out will focus on the iPod, Belkin has also brought out its Tunecast Auto, which wirelessly transmits audio from Samsung mp3 players to a car stereo via the cigarette-lighter outlet.

This, and the Tunebase are priced at £40 and £60 respectively.