They won't ship to you, you will have to drive and collect it.
Kenneth Olsen owns a site called www.korallen.no, you can call him (+47 for Norway) and ask him to contact his suppliers about getting a cuttlefish. He will ship corals but I don't think anything else. He is well-known in Norway among saltwater enthusiasts. He lives in Moss.
The fish store in Oslo is called TAM Alna. I bought an anemone from there recently and the guy I dealt with - Mats - had a knowledge that was second-to-none. They don't keep cephalopods in stock because of the difficulty of keeping them but they will order them in with 3 weeks notice I was told (I haven't actually done it yet so this is just what I've been informed). You would have to arrange a pick-up date with them. The number is 98 29 77 00. I would ask for Mats if you can, he was specifically recommended to me by the manager of another store.
Avoid Akvariemagasinet (Norway's biggest fish shop, in Oslo). The guy there was a complete idiot, I don't know how he makes any money.
You could also try Jan Holt AS, also in Oslo, I haven't been there but they are meant to be saltwater experts. I don't know if they can get you a cuttlefish or not, but they have an excellent reputation. Their number is 21 42 00 45.