Kicking off the network

Ok I have a Belkin wireless router. We have had problems connecting to the
network if we made it secured, so I left it unsecured, very aware that other
leaches would come and suck my bandwidth. So the question is, is there a way,
without turning off the router, to kick unwanted people off, like through the
command prompt or something? I tried to telnet, but it failed (ofcourse)