You could look at the OUI of the MAC addresses, first 3 octets could tell you the manufacturer of the device, see if it's any of yours.
If the leeching happens when no one is home I say you've got an external intruder, unless one of your PCs is on running BitTorrent or some other download.
You need to get off WEP, might as well have your AP wide open, WEP is so easy to crack.
If the leeching happens when no one is home I say you've got an external intruder, unless one of your PCs is on running BitTorrent or some other download.
You need to get off WEP, might as well have your AP wide open, WEP is so easy to crack.