Have you tried Google Calendar?
http://www.google.com/support/forum/p/Calendar/thread?tid=010152ccbf6bf103&hl=en
Windows Live Calendar doesn't seem to have a simple export ics file
option. Nonetheless you can still get the data across by temporarily using
the ICS feed it's just a little more long winded. I suggest the following
steps:-
1. In Windows Live calendar select "Share" and select your calendar then
mark "Share this calendar" and tick "Make your calendar public"
(temporarily)
2. You will see option to get the ICS link that says "ICS:Import into
another calendar application" - click that and copy the feed URL that
begins "webcal://cid-...."
3. In Google Calendar click "Add by URL" from the "Add" on the left hand
side, paste in the URL you copied in step 3 and make sure you tick "Make
the calendar publicly accessible?" You now have now have the calendar fed
into Gcal but not yet imported.
4. Go into the fed Calendar's settings under Settings>Calendars (click on
calendar name) and click on the green ICAL button and open the link in
your browser and copy all the all the ics code/text you see and paste into
a text editor like notepad and save as an ics e.g. mycal.ics
5. Go to Import Calendars in Gcal (Settings>Calendars>Import Calendars)
and import the new file you just made to your preferred calendar most
likely your primary and all being well your import is complete.
6. Unsubscribe the fed calendar in Gcal and return to Windows Live and
uncheck your calendar as Public to complete the process.
Tried to cut out steps 3 and 4 but I can't directly open the webcal feed
in the browser. This should be fine - let me know if you have any trouble.