I am using Exchange right now and am publishing a calendar to the internet.
It asked me to publish with the server's updating frequency.

MY question is how will this work for POP3 clients without exchange.  I read
somewhere that the update frequency is one hour.  Is that changeable?

I have some clients at a church that use OL2000 now and netfolders to share
calendars.  They bought licenses for office2007 and still want to share
calendars.  They are getting their mail from a pop3 provider on the internet.
I want to get them on Published calendars, but only if the updating
frequency is shorter than 1 hour.  

They are using server 2003 as a file share server, so I could use sharepoint
and have them share calendars that way.  From what I have seen playing with
this setup, you could not share your personal calendar through Sharepoint,
but each user could use a sharepoint calendar as their primary and be almost
realtime (with a refresh of the screen).  Just another option.  I want to get
as close to realtime as possible.

Ideas?

Thanks in advance
Gordon