This deal has ended.
Buy.com has the Kensington 33361 Micro FM Transmitter for iPods for only $19.95 after a $20 mail-in rebate valid through 1/28. Compare this to $47 at Amazon. This is a tiny transmitter that plugs into any dockable iPod and transmits music to an FM stereo location. Shipping is free and there is no sales tax (except CA, MA, MD, TN).