I've actually messed around with putting a camera on a helicopter,back when I worked for radio shack. It's actually not that hard but it's going to cost you around $400. We had a small wireless camera (which we powered with button cells), A ~$100 R/C helicopter and a video baby monitor.
Just for fun I Googled up some similar products which could work. (not saying it will be perfect)
http://radauto.com/shop/electronics/.../prod_103.html
This could be interesting for capture the flag games
http://www.thesource.ca/estore/produ...roduct=6011978
or
http://www.cobratoys.com/Cobra_S022_...r_p/l99260.htm
With these two items you could have real time video with a range of ~25m. Keep in mind most of your money goes up in smoke if someone lights them up or you crash.