For a long time (about 9 months since I got my iPad 2) I have wanted to AirPlay straight to my laptop which is connected to the projector in the classroom. After considerable searching I found a few semi-reliable apps that would AirPlay sound or video, but they would not allow mirroring.
In May
Airserver released a PC version of their software which allows wireless mirroring straight to my PC laptop. It is currently in beta, but available for purchase and free updates are promised (not that I have needed any). There is no sound at this stage, but on its way.
I purchased a teacher educational license for USD$5.99 through PayPal (you need to change your primary PayPal email address to be one that contains .edu) and now I have a license for 3 computers. I've already installed on my work laptop and my media center and it is working fantastically!!
The app on the PC opens when mirroring starts and closes when you turn mirroring off.
Applications:
I love to photograph students work - their way of solving problems or group work that they produce and project it straight on the board for others to see. Using my iPhone 4S / iPad makes this easy now and I no longer require an apple tv to get the job done.