In order to use IIS (to avoid port 80 being taken) configure subsonic to use a different port then setup a URL-Rewrite Rule:
Matches Pattern: (*.)
Rewrite: http://yourserver.com:yourport/{R:1}
To setup auto-login, first make sure the "Stop processing of other rules" checkbox is not checked in first rule, then setup as follows:
Matches Pattern: (login.view*)
Rewrite: http://yourServer:yourPort/login.view?u ... d=Password