A cycling map for the whole of Norway can be had in most big bookstores in Norway. It is called Sykkelruter i Norge and is at a scale of 1 to 1000 000. It has 75 planned tours marked and has some tunnelinformation as well. A useful website is
http://www.slf.no, the norwegian cyclist organization, they sell this map in their online shop. Maps are more often found in bookstores than in cycling stores here.