I have recently been converted to Google Wave.
I am a beta user, and have been very impressed.
If you have used Microsoft's OneNote, you will be familiar with multi-media documents that contain text, pictures, video, other documents, sound clips etc. Google Wave is like that, with drag-and-drop ease, except it is online, so you can access it from anywhere. And not just you. Wave is designed to be a multi-author tool. When you start a Wave you can invite others to join in (and they can invite others, too). So it is ideal for collaboration, either synchronously or asynchronously. Seriously, don't knock it til you've tried it. Just like when gmail started, though, you need to get invited to start a Wave. Or you can be joined on a wave, and then you're in.
As with most technological innovations, there are a range of pedagogical applications that can be imagined. Clearly, there are dangers of plagiarism. But you only need to be concerned about this if the individual is the only concept that your pedagogical system can tolerate. Google Wave was made for group work. (It should also provide a major boost for research groups - particularly as many of these are geographically dispersed these days.) When the product is the result of collaboration, the Wave offers ease and power. Try it.
Ride the Wave!
There's a lot more info here - a 1 hour-plus video
and here - a much shorter video.