There are numerous Oktoberfest events in Scandinavia - in Norway alone, you'll run across them in Oslo, Årnes, Kongsvinger, Eidsvold, and Strømmen. You can find an Oktoberfest near your destination in the article about Oktoberfest events in Scandinavia.
There's also a really big Oktoberfest taking place in Denmark. Each year in mid-September, the old Carlsberg site at Valby in Copenhagen is the venue for Europe's largest beer festival, aptly (but not very creatively) named the "European Beer Festival"!
And if you're looking for the original German Oktoberfest, go to the Oktoberfest Guide at About.com Germany Travel.

