The site has a nice collection of links to Norwegian-American resources. NIV applicants should submit applications in person or by mail. The only time a visa application by mail are not accepted is when the applicant is in the US on the Visa Waiver Pilot Program. There is reciprocity visa fee for Norwegian nationals, though this fee may apply to third country nationals applying in Oslo.
Applicants can typically collect their visa the day after the application is submitted .
When the consulate is satisfied that the applicant has all documents in order, they will then schedule a doctor's appointment and an immigration interview. Norwegian Kroner equivalents are acceptable.