Domino for IIS is a viable option. There is a tab in the server document (Internet Protocols//Domino Web Engine) where you set this up. This lets you use IIS for non-Domino HTTP calls. It works well, but it can be difficult to setup. I suggest starting with a fresh server that has IIS 5.0 installed and configured prior to installing and configuring Domino. It makes for fewer conflicts between the two. Domino will even prompt you about using IIS during the install/setup of the server.
This was first published in October 2002