Switzerland has ratified a recent trans-European proposal that legitimises iPod FM transmitters, such as the iTrip FM.
Iceland has already ratified the new agreement, which permits the use of low-power, low-range devices. Other European countries - including the UK - are also expected to agree to the deal.
Use of such devices has been illegal under European laws until now. Pending ratification of the new law, dealers selling such devices remain threatened by local regulators, who continue to seize assets and levy fines.
Legitimising such devices will also enable manufacturers to apply for a "CE" safety mark to carry on their devices.
iTrip FM manufacturer Griffin Technology told iPodLounge: "This means that iTrip will not conflict with other electronic devices, and that it will be available to a wider European market."