The preponderance of capital letters in reader M.M’s message hints that he's got the wind up due to an unexpected entry in Leopard’s sidebar. In a message titled POSSIBLE SECURITY ALERT: IMPORTANT, he writes:
I recently installed Leopard and set up Back to My Mac. Two days later, I noticed a PC server listed as “thomson” under my Sharing header in the Finder window. I can connect to it as a guest.
DOES THIS MEAN THAT SOMEONE HAS MANAGED TO INFILTRATE MY COMPUTER BY SUCCESSFULLY INSTALLING THEMSELVES AS A SHARED DEVICE VIA BACK TO MY MAC? If I’m not being a complete idiot and not done something stupid, could I be IN DANGER?
I'll put down a fiver that says British Telecom is your ISP. Some BT-branded routers are re-branded Thomson SpeedTouch routers. What Leopard is showing you is that router.
Just so we’re clear:
YOU HAD EVERY RIGHT TO BE CONFUSED, BUT YOUR COMPUTER IS PERFECTLY SAFE.