Here is a summary from the VG article the confirms the above mentioned guests after having contacted the different courts and in addition the following
Princess Ragnhild and Erling Lorentzen
Haakon and Martha Lorentzen
Princess Astrid and Johan Martin Ferner and children
King Albert and Queen Paola
Prince Edward and Sophie Wessex
Princess Anne and Timothy Laurence
The Grand Duke and Grand Duchess of Luxembourg
King Constanitjn and Queen Anne Marie
Probably Pavlos and Marie Chantal
Princess Kristine
Yesterday Birthday director Bentein Baardson was on a tour of the palace park with people from the court and the city of Oslo. Baardson is the official Norways "partyfixer", whenever there is something that shal be perfect he is in charge, like the opening ceremony for the Lillehammer Olympics, the Ibsen year, the events around the Crown Prince wedding.
21 Febuary, National Celebration
Stortinget (parlament) will honour the King with a ceremony right outside the Palace, here the King will get the gift from Stortinget, according to VG it is a staue of his mother that will stand in the north end of the park, in the south end there is already a staue of his grandmother Queen Maud
A service in the Trinity church
Dinner at Akershus, hosted by the goverment
23 Febuary
900 guests will gather in city hall, all the mayors in Norway is invited, so is all the county-mayors and countymen, according to the city of Oslo, only 3 people have turned down the invitation. Also royals from abroad will be at this arrangement. The event will las an hour and a half and all the 21 countys are invited to give some cultural performance
After that there will be a "family dinner" at Skaugum
24 Febuary
There will be an event outside the Palace in the daytime, what kind of event is a secret, but Queen Sonja is in charge
In the evening there will be a gala dinner with dancing at the royal palace.
25 Febuary
There will probabaly some sort of joint event in the morning before the guests leave
there will be some more events but according to VG it is secrets and the court is trying to make some suprises for the King