I've just finished my first day of teaching with the iPad. Here's a quick summary of what worked and what didn't.
First class was Higher Computing. We were revising notes in a discussion format. I used GoodReader to have my PDF copy of the notes available to me as I taught. The iPad was MUCH more convenient than being tethered to a laptop or desktop machine to refer to the file.
Second period was a free period. I used the iPad to check the news on the ash cloud and compose a short Keynote presentation with URLs for use in the next two classes.
Next two periods were junior computing classes. We're focusing on the general election now, so I used the iPad to present the keynote slide of URLs I wanted the kids to spend time browsing, looking at the various parties use if the Internet, social media and online video.
Lunchtime, I used the iPad to do some system administration tasks on our server using iTeleport. iTeleport is an iPhone application, but it worked very well on the iPad. I'd like to see a dedicated iPad version of Apple Remote Desktop, but the iPhone VNC clients worked well as a stop-gap.
Last two periods were a bit disrupted due to large chunks of those classes still stranded around Europe, but I would have been working with existing paper materials in those classes.
After school, I ran an in-service course on our use of Basecamp. Basecamp mostly works well on the iPad (file uploads are tricky though). I couldn't use the iPad at all for this because it can't project a web page. Mobile Safari only works with a projector when playing html5 video.
So that's pretty much a typical school day for me. The iPad worked well, within it's known limitations.
It won't do everything, though. I couldn't teach my Ruby programming class from an iPad, for example. However, it's a very solid device for the vast majority of computer based activities in school, so far as I can tell.
One of the best things? It's ten minutes until the end of the day, I've been working on it all day and the battery is still at 56%. this alone makes it a really big deal for education. I know of one local school that has a trolley of laptops lying unused because they can't get Health and Safety approval to plug them into the wall in the classroom.