OK...after better keyword choices I did find that the 'change location' solution does work, but only if the calendar is first shared with the world, and then has its location changed:
Does anyone know if information in public calendars can be found in nefarious ways (like by Google)?
FWIW, I did try sharing privately to just myself, so that I could then subscribe to the calendar on the serving machine and push it out as a .ics file...but I cannot share a calendar with myself. Boooo.
Calendars which are listed under 'On My Mac' can be published in the old way, but willl not sync to MobileMe. Calendars which are listed under your MobileMe login name can be shared publicly but have to be read in a CalDAV client - this includes iCal for Mac users or Google Calendar for non-Mac users. Please see this page:
They don't really have to be read using a CalDAV client---what I do with them is use PHP iCalendar (http://phpicalendar.net/documentation/index.php/Main_Page) to publish them as a web page. (This was alluded to in the radbrooks link above.) When they are published on a private server, they get pushed as an .ics text file instead of the binary cache files which are used by the new MobileMe.
So...sharing via a webpage is still perfectly doable. Sharing privately via a webpage seems to be a problem.
I did try everything I could when searching on Google to sneak into a calendar being shared from www.me.com, but could not come up with anything.