GMail recently added a feature that makes it easy to subscribe to official holiday calendars for a variety of countries. Also included are sports schedules, star dates, and (maybe more interestingly) an automatic birthday calender based on your contacts.
I can't say I really care so much about the Swedish holiday calendar though, it doesn't even include Midsummer Eve or Christmas Eve, arguably the two most important days in Sweden. Sure they are only de facto holidays, but still. I'll stick to the nice iCal holiday generator over at oops.se for the time being.