Logitech, which makes plenty of PC speakers, has now moved into the tablet arena with the aptly named Logitech Tablet Speaker.
While it isn't wireless, at least it doesn't require a power adapter: the built-in rechargeable battery drives the speaker for up to 8 hours and charges via USB.
We got a quick look and listen to the speaker at a recent Logitech preview event and it certainly offered better sound than the iPad's internal speakers. Just don't expect a whole lot of bass (we'll wait to pass final judgment when we get our hands on a review unit).
While you see the Logitech Tablet Speaker ($50) pictured to the right with the iPad, it works just fine with any tablet. However, it is designed for larger models. When you clip it on, it acts as a stand and tilts your slate up at about a 20-degree angle.