It's a web based system. You enter all relevant information into a webpage and submit it, wether you was involved in the accident or just an witness is not important. What's important is getting the data. Information is then reviewed and entered into that years statistics.

Typical fields/questions are:
Contact information:
Time and place for the incident
Weather conditions
Terrain type
Traction/friction (snow, rain etc..)
Name/age/experience level of persons involved
Description of injuries
Main purpose of the trip undertaken (climbing, hiking, rapell, glacier walk)
Organized event
Activity when the accident happened (climbing, descending, free-climbing etc.)
Type of incident (fall, rockfall, glissade etc)
Short (terse) description of the incident
Why did the accident happen (multiple choice and free text)
Safety equipment in use
What could have been done to avoid the incident
Rescue, What, when, how, who, experiences from the recue
Other comments

All this information except contact information and names are then made available to the public, and at the years end a report is put together and the statistics updated. Out of these reports, it has been shown that inexperienced climbers are the most prone to accidents (no surprise there), and that experienced climbers mostly have accidents while returning from a trip. It has been quite useful.

The web form is available here (in norwegian): http://www.klatring.no/sikkerhet/pages/formUlykke.asp