By Katie Marsal

Published: 05:00 PM EST (02:00 PM PST)

Apple Inc. is teaming up with HD Radio to offer listeners a new feature that will allow them to "tag" songs they hear on the FM dial for a later purchase via the iTunes Store.

Dubbed "iTunes Tagging," the complimentary service will work with a new breed of HD Radios receivers that will come equipped with a special Tag button. Polk's I-Sonic Entertainment System 2 and JBL's iHD will be the first products to support the feature later this holiday season, with several additional systems are expected to follow early next year.

"When a song plays on your HD Radio that you like, a simple push of a button will tag it and later give you the chance to preview, purchase, and enjoy it with iTunes and your iPod," said Greg Joswiak, Apple's vice president of iPod Product Marketing.

Initially, iTunes Tagging will be implemented by several major broadcasters across hundreds of stations, according to Bob Struble, chief executive of HD Radio creator iBiquity Digital. He said additional stations and broadcast groups are expected to join soon, with a formal announcement of participating groups planned for later this month at the NAB Radio convention (September 26 - 28).

Among the big name broadcasters already throwing their weight behind the iTunes feature is Clear Channel Radio, which has promised that all of its FM stations broadcasting in HD digital radio will be available on the new HD Radio receivers. It's also urging all radio broadcasters to fully support the new capability.

For those who don't know, HD Radio is a brand name iBiquity's method of digital transmission of AM and FM radio stations. HD Radio systems are unique in that they allow stations to broadcast high quality audio and a variety of text-based services, as well as additional FM channels, without changing to new frequency bands. ("HD" in HD-Radio stands for "Hybrid Digital" not "High Definition" in more popular usage.)

HD Digital Radio Alliance, the coalition of radio broadcasters formed to promote the radio technology, said it is "tremendously excited" about the new iTunes feature and plans "a multi-million dollar advertising campaign focusing on the JBL and Polk" receivers later this year.

Thus far, there's no information on how JBL's iHD will interface with iTunes. However, Polk says the display screen on its upcoming I-Sonic Entertainment System 2 will indicate which HD digital radio stations and broadcasts have songs enabled for the service. Information about tagged songs will be saved to the system's memory and transfered to an iPod when docked. When the iPod is then connected to a Mac or PC, iTunes will automatically present the song information from the tags in a new "Tagged" play-list.