I just searched for a possibility to sync my N95 and iCal with google calendar. I don't really know why I would want to have my calendar available online when I'm carrying it arround in my cellphone anyway, but it felt like the right thing to do ;)
When I searched for a possiblity I stumbeled across Goosync . It basically does what it's told to, sync my N95 with google calendar using SyncML.
What you have to do is:
a) sign up
b) select your cellphone and send yourself an auto-configuration SMS
c) enable Goosync to access your google calendar
d) select the goosync-profile in your Phones "Sync"; Properties
Configurable Sync WindowYou can select +- 365 days, allowing you to sync any events that fall within this sync window.
In the free version, each sync has window of plus 30 days and minus 7 days from the sync date. That's ok for me though
EDIT: http://www.scheduleworld.com does a decent job too and can also sync contacts and notes. Although it somehow messed up the timings on my appointments as far as I can tell…