On Gotland they still make oldschool vikingbeer. They call it Gotlandsdricka (drink):
http://sv.wikipedia.org/wiki/Gotlandsdricka
my translation:
Gotlandsdrink is a form of the older type of beer that was brewed in Scandinavia during the viking age and the early middle ages. Since hop during this period was unknown up here (in the north), they used juniper or myrtle to flavor the beer.
Gotlandsdricka, more often called "Dricku" or "Dricke" is an old beer like drink from Gotland, the large island sort of on the southeast part of Sweden.
Usually they have smoked malt, juniper branches, low bitterness, if hops is used it is in small dosage.
I would not say that this is traditional for Scandinavia, or even Sweden, but for this actual island.
In Finland they have Sahti, in Russia they have Kvass, similarites exist, but they're worlds apart.
When it comes to what beer was flavored with before hops, there are many different things, rather usual was "pors" (
Myrica gale), but also "skvattram" (
Rhododendron tomentosum), "älggräs" or "mjödört" (
Filipendula ulmaria L.), but also juniper, lingonberries etc.
I got this old book where they tried to chart all the things used in various parts of Sweden over the years, as far as they've found evidence for, but don't have it all in my head.