well, according to what I've found googling around, it's imposible... (maybe with with windows xp 64...)
but I thought that maybe someone could find a way to achieve it, or at least some workaround...
http://www.iisanswers.com/IISFAQ.htm
-- ps: I need to debug classic asp code, and my production environment is windows 2003, while my development machine is windows xp...
-- edit: just to clarify, I can already debug classic asp code in iis 5 with vs 2003 and 2008, it's just that I stumbled upon a (very silly) bug that only appeared on iis 6 (when IIS 5 received and empty http status, it just assumed 200, while iis 6 kept asking for my credentials in an infinite loop, it was very silly in deed, but took me a lot of time -and cursing- to discover it)