wireless checking

[#1]

is there any tool/program that will tell me who is downloading on a wireless network?
im the hard wired admin and have 2 other pc's connected to the network,
ive set wep security
ive set mac address filtering
so on my dchp list i only have the 3 pc's showing.
when i try an d play online games i have a terrible ping 300+
i asked the kids and they all say no,
so i want to catch them out
any ideas?

[#2]

Block access from their MAC Addresses?

[#3]

the only way i can block them is to delete them from the list,
i have a "Belkin  F5D7633-4"
any other ideas?
or if you know a setting i can use?

[#4]

I had a quick Google and found this page where you can download a flash tutorial for your router. It does have a bit about access blocking for an individual or range of PC’s based on protocols. Don’t know if it will help you.
Regards, P.

[#5]

You can set them up to connect via a proxy if your pc is always on and that can log everything they do get a free one from
http://www.youngzsoft.net/
or get whats transferring free from
http://www.wfshome.com/software.htm
you can then sniff everything they do

[#6]

il have a look thanks guys

[#7]

Did you get any further with this Slick?
I have notice that my off peak usage was 6MB on one occasion and my PC & Laptop were both switched off at he time.  Maybe I am paranoid but I have now changed the SSID and the WPA password (the SSID never has been broadcast and MAC address filtering is on too).