Short distance broadcast to be legal in the UK – e.g. Tunecast

So far in the UK it has been illegal to use devices which broadcast radio signals to an entertainment FM radio receiver. This means that using devices to broadcast from an iPod, or a mobile phone to your in-car entertainment radio was illegal, although these are available and in use.

With a change of heart from Ofcom As from the 8th December these will be allowed as long as they are low powered so as not to interfere with other devices. So at last these will be legal.

VNU News Story – Ofcom legalises iPod radio broadcasts

This is not legal advise. You need to check that the individual items are covered by the new Ofcom regulations.