Damnit, work makes it so i cant check the board often so giz got here first but....
Many radio stations already do broadcast song information along with the audio signals you just need the right type of radio reciever to see the data and the stations need the equipment to broadcast it.
This technology is called RBDS (Radio Broadcast Data System) in the U.S. which is based on the european RDS.
If you want it for your computer check this out it has some usefull info: http://www.dvdirect.com/pdf/ADS/5013.pdf
Ill get more info when i get home hopefully or talk to you in IRC.