Whats wrong with Hotmail?
Hotmail is an Americas-based free e-mail provider which is very popular, largely for the reason that it got there first. Attempts by its owner to convert the servers to their own operating system have all so far failed, and it continues to run Unix-based software. The front-end runs off Windows 2000: http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windows2000serv/case/hotmail/default.