In reply to Lynsety:
It really depends on their ages, most childcare, as in slope side dagis/nursery is aimed at the youngest as by the time people kids are 8 or 9 they will ski most of the mountain and all resorts have dedicated kids ski areas, easier tows, travelators etc..
Hafjell has a creche at the bottom near the beginners zone. Kvitfjell and skeikampen I've never seen anything, but they have kids ski areas.
Salen, especially Lindvallen is very kids orientated. Not sure on Are or Hemsedal though as I've never paid attention or been there with our kids yet, but skistar websites are in English too.
The biggest thing is sking tends to be a family activity, free passes for under 6s with helmets in 99% of places etc.. the adults fit their slope time around the kids, evening floodlight sessions and many bigger places often run a couple of lifts from 7am.
All will have English speaking instructors for kids. Things to consider, weeks 7-9 will be spring half term, varying on councils, you will struggle to get booked now for then. Youth Olympics mid feb in Lillehammer valley. Plus the last weekend of feb through to first week of march cross country ski races everyday starting near Salen. Plus a few other big events at other resorts, Are is the fall back resort for alpine events if the alps has a poor snow season.
EDIT - I tried to spell the places properly, but the website keeps turn them back to gibberish, so Are and Salen need different 'a's.
One other thing to consider is the cold if you bringing little ones, depending on the winter it can be a little bitter at times. The bonus though is lift queues are absolutely minimal and there are very very few idiots on the slopes. People go to ski, not party.
Post edited at 20:31