Computer/Stereo Audio In Every Room?

CmdrPorno asks: "I've been looking for a way to listen to MP3's without physically connecting a computer to my stereo. Ideally, I would be able to listen anywhere in my house. The popular FM modulators, such as the Arkon, seem like an ideal solution, with only one problem: the Web site states the modulator will only transmit four to six feet. Is there any way to tweak one of these modulators to transmit a greater distance, or does the device I'm describing already exist?"