Have you guys heard about the pringles can trick? I first heard about it from some professors on campus that were monkeying around with the wireless network on campus.
You can check out a good article on it here:
http://www.oreillynet.com/cs/weblog/view/wlg/448
This website talks about cantennas also, and how they compare to pringles can antennas.
http://www.optonline.net/Call_For_He...098863,00.html