There is actually quite a bit you can do with a little know-how on an unsecure wireless connection. I got $150 to setup my neighbors wireless router and firewall, I enabled WEP. He initially just bought the router, but I showed him that it needed to be secured by printing 101 uses for sporks on his printer. He offered the $150 to setup security, install a firewall and get everything fine tuned. Took about an hour.
Oh incase you wanted to know about 101 uses for sporks:
http://www.angelfire.com/punk/spiffyangel/101uses.html