I'm using Windows XP on my development machine (IIS 5.1). I installed hmailserver on my machine and now want to configure IIS to relay all outgoing messages to hmailserver, what should I do in IIS to do this?
You're looking for the Smart Host setting. It's in the "Advanced" settings on the "Delivery" tab of the SMTP server's properties. Set that to the name of the desired destination mail server.
You'll also want to allow relaying from whatever address(es) will be generating the email. That setting is under "Relay" on the "Access" tab of the SMTP server properties.
Set those two items and you should be in business.