OSL Gardermoen airport is about 25 miles from Oslo City. The train apparently costs £35 return. Prices are extortionate, especially taxis. Although a large airport, facilities are limited. There is a small kiddies play area at Arrivals. Nothing is worth buying in Duty Free. There are numerous expensive small food outlets. The best thing for the kids is handcuffs and gags and colouring books. Don't go without Ipod (on loud) and PSP, though your wife may not speak to you again.