9to5Mac is reporting they’ve received a tip that Apple is developing an FM Radio app for the iPhone and iPod touch that will have background multi-tasking (like Apple’s Phone and iPod apps), and may be able to pause live programming like the new iPod nano radio feature.

It will either be provided as a stand alone app, or integrated into the iPod app, but it’s still a work in progress:

The holdup on this app is that Apple is trying to integrate the Mobile iTunes Store purchases into the functionality of the program. For instance, if you like a song you are listening to on the radio (and that station supports tagging and you are in the US), you will be able to push a button and see the song (and all of the information around it) in the iTunes Mobile store. With another click, you’ll be able to make a purchase. This is an extension of the Song Tagging feature used in the iPod Nanos. Perhaps they could even add some Shazam technology to help with those stations that don’t support tagging.

9to5Mac further claims that existing iPhones and iPod touches have been technically able, though not yet enabled, to receive FM Radio for a while now, and that the iPhone 3GS and iPod touch G3 can even broadcast FM Radio as part of the Nike+.

While rumors of FM Radio functionality, and radio tagging surfaced before the iPhone 3GS shipped, and the chipsets may have such technology as part of their overall package, it’s unknown how easily Apple could “flip the switch” on full FM Radio — the way they did for Bluetooth Stereo A2DP on the iPod touch G2.

Still, given the iPod nano’s radio feature, and under the cliche of better late than never, if Apple does indeed add Radio.app or just build in a Radio tab to iPod.app, were’ sure some users would be happy. Right?

[Small-print disclaimer: Image above represents iPod nano radio app composited onto the iPhone 3GS]