I just downloaded and installed the very useful IE6 Compatibility Virtual PC [IE6-on-XP-SP3.exe] from Microsoft. Within minutes of starting the machine and getting distracted, the screensaver kicked in, locking the machine until I entered the relevant password for the IETest user. The password is P2ssw0rd.
This information wasn’t immediately obvious via Google so I thought I’d post it up in an attempt to make it more findable by other folks. I actually got the information from Eric True. Thanks Eric!