another good idea is to limit your scope to only be large enough to handle your home computers....if your router allows this...normally by default you can put 253 computers on your network....a scope of 192.168.0.1-255...1 being the router...narrow it to 192.168.0.1 to 192.168.0.3 if you have only 2 computers...they'll never get an ip addy and hence they can't connect.
Or don't broadcast your SSID or do the MAC address lockout or the WEP or WPA options....
if a user can just connect, (as I can at a friends) its funny cause his linksys has obviously retained its default password for access...all you have to do is type 192.168.0.1 and then enter what the manual says for linksys (all the same)....can you say change password, mess with it (until he resets it)....
Just something to think about....I think it is very rude to screw with someone's wireless router if you're downloading and serving illegal music through it. Just my belief is all.
(that's all a joke) but a serious topic to think about....