The Speaker Dock 2 from Nyko lets you listen to your music via the stereo speakers while charging your iPod at the same time. It runs off either 4 AA batteries, or the included AC adapter.

It’s small and compact, so it can be placed anywhere space is limited. And there’s also a pass through dock connector so you can perform simulatenous file transfer while charging.

Features:

* provides clear stereo audio and adjustable viewing angles, ideal for watching videos
* acoustically balanced sound from two BDD Proâ„¢ speakers for accurate audio monitoring
* amplification circuitry provides increased volume levels and deep bass, without sacrificing balanced acoustics and sound separation
* larger sound cavity and vents allow for deep bottom heavy bass and higher sound output
* portable design powered by 4 AA batteries — ideal for outdoor activities
* interchangeable cradles allow compatibility with iPod, iPod with Video, iPod nano and iPod mini
* includes AC adaptor — charge and play your iPod at home or office without batteries
* pass through dock connector makes it easy to charge the iPod, listen to music and transfer files simultaneously
* listen to other devices like MP3, CD or cassette players via the ‘Line in’ port and stereo cable.

Source.