There's always exchange if you need to access the calender and everything across multiple computers but it's certainly not free
I pay about £5/month for a 3gb exchange account
Still might be worth it if you need to have the calender synced but need to have outlook running on multiple pcs at once.
Also syncs nicely with Windows Mobile based devices, Which when combined with a decent data plan is quite handy.
Did mean I didn't lose my contacts when I managed to lose my Pda/Phone
