Kev,
The workpermit i think is good for one year then you have to renew it (and you guessed right there is paperwork and a trip to the INS (or whatever it is called now)). Usually after you have had a work permit for a while you can apply for a permanent resident card (aka green card), once you have a green card it is good for 10 years. Depending on how you enter the country you might be eligeble to apply for citizenship, once you have that there is no more paperwork.
(Norway does not allow dual citizenships and I have not made up my mind if I want to give up my norwegian citizenship so I have not applied for a US citizenship yet)
Here is the link to INS: http://uscis.gov/graphics/index.htm
lots of good information

Einar

>Thanks.
>
>So the work permit allows basically working and residence? For how long? Do you have to renew that permit at all?
>
>Kev