Here’s a tidbit from Apple’s site:
Video mirroring makes it possible to share what’s on your iPad with an even bigger screen and an even bigger audience. Which is huge for your movies, photos, presentations, and lessons. Just attach the Apple Digital AV Adapter (sold separately) to your iPad, and you can watch a movie in your living room on your HDTV. Give a presentation in a conference room on an HD projection screen.
The adaptor will set you back $39, but in my book, it’s totally worth it…
Currently, getting video out of an iPad is a mess. Some games allow for it, while some don’t. Keynote can play slides on an external display, but there’s no way to get the entire iOS experience on a larger screen. This will allow presentations to be held in something as simple as the Photos app, without the need to build a Keynote document.
I can see several educational advantages as well. Teachers will be able to walk students through material much easier, and IT departments can now hold seminars with live images straight off of an iPad, not just screenshots in a presentation.