The newest, hippest thing to hit the internet is Google Wave. It may become the next big thing to use in the web-enabled classroom. It's hard to say for sure - you need to be "invited" to get a wave account, and then you have to figure out what it does.
At first glance, Wave looks like just another form of email. But when you start to use it, it starts to feel more like a web discussion forum, and a little like instant messaging, and kind of like a wiki too. It really takes elements of all of those tools and combines them into something that is different from them all.
What problems does Google Wave Solve
may help in deciphering what wave is all about. It points out the flaws in existing technologies, and how Wave attempts to merge different solutions to address those problems. While that addresses business use, it's easy to see how this can transfer into the classroom.
We are just starting to toy around with Wave here at CTAAR. Let us know if you have an account and want to share or just see what we are doing.