Synching iPhone with internet calendar (.ics)

I found the answer to my particular issue. The reason that my iPhone could not subscribe to a published Outlook .ics calendar was because the MIME type of the .ics file was wrong. As recommended in this brilliant post by Joe Bradford, I went into IIS, changed the MIME type from application/octet-stream to text/calendar, and iPhone could connect and subscribe without further issue. Success!

PS: I did not run into the second issue that Joe chased down, which was having to remove the Byte Order Mark (BOM) from the .ics file via a hexadecimal editor.

In most cases, you only have to slide the calendar to 'ON' in your exchange settings. Settings > Email, contacts, > your account > switch Calendars to ON.

simple as that.