How about a good ol' baby monitor??
But if u insist on building ur own, i recommend this circuit cuz its real simple and works great. It'll transmit 100 feet or so with a piece o junk clok radio (1/4 a mile with a nice radio). I would also recommend hooking up a wall transformer to the circuit so u don't have to worry about battery. Anything from 3-12v will work (obviously if you give it 3 volts, it won't transmit as far). Hope this helps. Hollar if u need help with the inductor :lol: