Microsoft has a tool available for download to kill off the various mydooms.
I’m in the middle of advising my uncle, who recently got broadband, how to protect his PC better. Broadband should perhaps come with a health warning for the IT un-educated along with a set of tools (a first aid kit?) to repair damage caused already and a set of innoculations to prevent further damage. I would have thought that BT or any other provider would have insisted that appropriate technical contraception is in place before allowing a connection to their proxies – after all, if people using their services get infected, the load at their end is increased and therefore their costs are higher. So it should be in every providers interest to provide firewall and AV software for everyone, with the AV running at the server end eliminating viruses on the way through.