I'll take your word for it:

Q. Why do I have an 'Automatic Tunneling Pseudo-Interface' interface?

A. IPv6 in Windows XP and Windows Server 2003 uses the 'Automatic Tunneling Pseudo-Interface' for encapsulating IPv6 packets with an IPv4 header so that they can be sent across an IPv4 network. By default, IPv6 configures a link-local Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) address on the Automatic Tunneling Pseudo-Interface. The link-local ISATAP address has the form fe80::200:5efe:w.x.y.xor fe80::5efe:w.x.y.x, in which w.x.y.x is an IPv4 address assigned to the computer.