You should also be aware that February is the period of "sportlovet" the school winter vacation period. Especially week 9 (starting Feb 28 2010) when Stockholm is off everything up in the mountains will be very crowded and very expensive, but also the two weeks before that when other parts of Sweden are off will be less nice.
Personally I would suggest that you go in later in March, less crowded, more chance of sunshine, less risk of temperatures below -20 C where there is quite a risk of freezing injuries if you are not used to being outdoors in the mountains. Also the daylight hours will be longer so you will spend more time out doors.
Prepare yourself carefully as the weather in the mountains can change extremely quickly and you should know what to do if you get caught in a snowstorm. You must also have clothes suited for the climate.
Henrik
