In reply to laurentb:
hey
we went there last year for a week, i had never been before either but i want to go back for definite,
we booked cheap flights which you can do with any cheap airline flying to oslo, think we paid about £70 or something like that, just be careful with baggage costs! try booking sports luggage for all your climbing gear.
car hire we got from the airport in oslo but you can book that in advance to get a better price, we had 2 golfs for the week which was great for the 8 of us, think it was only £30 each or something like that. its about a 4 hour drive to rjuken if i remember rightly.
accommodations wise try looking on here
http://www.rjukan.co.uk/ not sure where we booked ours because a friend booked the apartment but you can get some good places for cheap online, think it was about £40 each.
all the walk ins are about 5-10 mins from the car parks so you can relax when your climbing.
food and things are expensive in norway so i wouldn't eat out if you can help it, most places you find to stay have good cooking facilities so i would eat in house.
we took £100 spend with us for food but i would prob take £200 just to be safe,
all in all i think it cost me about £300-£400 but it was worth every penny, just make sure you take plenty of ice screws with you, and plenty of warm kit, which i know speaks for its self but when you are belaying, there can be a lot of standing around in -15 to -20 degrees with no sun light, its a lot colder than Scotland especially on your face, my friend got frost nip on his nose from about 20 mins of belaying.
and take lots of dvd's because booze is so expensive and its dark about 4 in the evening so you will be sat around a lot.
hope this helps
Sam Wall