ok, the connection and the disconnection is a problem with leopard. if u look at the airport icon and click on it, u'll see tht leopard keeps on scanning for networks even when u connect to a network. then it disconnects u to update the refreshed list and tht is why u keep getting disconnected. i face the same problem when i have more than 1 routers in range of my macbook. apple still hvnt come up with a fix for this
i cant use my macbook@skool due to this problem. highly frustrating