For what it's worth. Microsoft has killed the servers for automatic activation of Windows XP, but as far as i know, the call in and get activated, phone number, & service still works. It's a couple of months since i used it on a virtual machine, but i haven't heard anything bout them killing it of.
Also, for updates... There is a registry hack
to trick XP in to thinking it's "Windows Embedded Industry" which makes it download security updates and patches that came out during the last 4 years, after "official support" was terminated.
If applying, FIRST download and update as far as you can with the regular service.
If anything, i think it sucks that they are developing all these security patches, but wont release them for actual XP users.