Apple TV does not handle WPA Enterprise security, which of course my school, and most others, uses on its wireless network. So now what? Well I put it out there on Twitter and got some help from @dicko_nz and @mrrobbo. In the end the method of connection I've gone for is to turn my laptop into a wireless hotspot using a free program called Connectify Lite (you can upgrade to the Pro version for $30.35). This allows me to run Apple TV and the iPad2 from the laptops wireless hotspot. This worked at home and I connected both to the laptop hotspot, but that's at home! The theory is that by doing this at school I will be able to somehow bypass the WPA security at school. Thanks to @mrrobbo who referred me to a post by David Hinson saying that he got the hotspot method to work. Unfortunately the school's wireless system is down and as it's the school holidays there is no one to get it back up so I can't try out my plan.
If this does not work I will be extremely disappointed in what is, along with the iPad, a potentially great educational product. Even if the above method does work it still requires some leg work to get it to run as it should.