Mat, thanks. I ran into your code last night and tested it for the iphone in a non-anonymous environment. Did not run ad hoc, but I found the changes needed:

a) Mime type of the ical.ics Page should be set to text/calendar. This setting is great, because when you send a link to the page, the iPhone will automatically jump to the calendar subscription page.

b) Username, servername and Password in the subscription. Use the server name that the domino server has as Fully qualified Host Name instead of hostnames in internet sites. Before I did this, the iPhone said it could not verify the account in some cases. If I used my short name to log in, it did not mutter, but also did not show the calendar entries. after using FQHN, I could use my long user name and pw and it also shows the entries now.

c) You might want to filter substrings from the subject field, like the colon to not confuse the format.