I use Audacity to edit songs into RTs by choosing the 15 second clip I want and save it. You have to dl a LAME encoder an install it into the program's files. I don't remember if you can alter the gain of the track with it. I use Mp3Gain for that. It's a lot easier to use then Audacity and the track has to be an mp3 (duh).
BB 8900 Tmobile, Moto Droid Verizon