well looks like this can only work on 2.2 anyone can port it to ics or jb?
No, I don't think so.
Only the stock 2.2 has the transmit code enabled in the Broadcom OEM FM API. The needed code was removed/disabled for 2.3 GB and AOSP based ROMs usually don't use the closed source Broadcom OEM FM/BT API. They use the open source Bluez stack, or the new open source Google/Broadcom "Bluedroid" BT API.
I didn't create the app. Somebody who once worked for T-Mobile sent it to me and I made it available on devhost. I've since removed it from my devhost files, but fortunately other people have copies now.
The story is...:
T-Mobile was looking to release the transmitter app as a stock feature. For some reason, they decided not to; perhaps for the same reason that virtually NO "western/1st world" phone OEM has ever officially supported FM transmit (except Sharp for some Japan domestic market devices). Reasons are debate-able but could include extra delays/hassles/costs for FCC certification and/or the low quality of FM transmitters on a chip.
So, ... this phone is one of the very, VERY few Android devices that has the FM/combo chip transmit antenna pin connected somewhere useful, ie the wired headset cable.
I bought 2 of these phones, used, a while back just for this reason. I was going to reverse engineer the transmit functions / registers, but never got around to it. I don't think I'll ever get around to it now.
And I have very serious doubts that anyone else is going to spend the time required to figure this out, especially on such a "legacy" phone now.
So that's it. It works. But ONLY on stock 2.2 and ONLY on this phone.
And the signal is pretty damn weak. I have to wrap antennas together to get a half decent signal. And even then the quality doesn't seem too good. Wires or Bluetooth are better ways to send audio.