Source: http://lifehacker.com/5606701/the-sprint-anycom-stereo-receiver-makes-your-ipod-speakers-wireless
We're not partial to unitaskers here at Lifehacker, and the slew of popular iPod speaker docks are no exception. While they're mighty convenient for your iDevice with a dock connector, they're less so for your other media players and smartphones, especially if they don't have an auxiliary jack. The Sprint Anycom FIPO Bluetooth Stereo Receiver, apart from having a ridiculously long name, is a $20 adapter that plugs into your iPod speakers and makes them wirelessly compatible with any bluetooth-enabled audio player.
That means your iPhone, 2nd or 3rd generation iPod touch, Android phone, BlackBerry, and even Laptop can pair with it and play music into the speakers. Sure, the audio quality may not be audiophile-approved, but it's not like it's a $1000 stereo—it's an iPod speaker dock, and $20 for wireless, anything-compatibile music playing is hard to turn down. Hit the link to check it out.
Update: Just after we posted this, Amazon changed the status of the item to "currently unavailable". If you search around, though, you can probably find it available on other sites.