[brodle]

If you look in system Information on the required machine then it will list all the mac addresses ( Lan Mac, Wireless Card Mac etc ) I have some network software which displays mac addresses of all machines on my network I also have a packet viewer that I can check traffic on my network I.E Ip addresses, Mac addresses, Packet Data, Host Names, Vendors etc Its good to have some software as you can keep a check on what connections are leaving your pc so you can make sure your firewall is doing its job and you can keep an eye on how well your router is performing like dropped packets etc also you would notice if someone is using your network without permission.

Another fast way if you are running XP is to open up a command prompt window and type ipconfig /all and you should see it under physical address. along with your dhcp, router address, subnet mask, host name etc.

To see what computers are actually connected to your router then go into the router software by typing 192.168.xxx.xxx or what ever your DHCP is server and look under DHCP client list.