This valve adaptor rocks. We get a wide variety of kids bike and pram wheels coming into the shop to be pumped up and this thing saves us our bacon so many times.
Great for home use too. In addition, try to buy innertubes with right angle valves (bent valves) where small wheels are concerned. They leave more room for the head of the pump to access the tube for pumping. For example, popular pram tubes that we sell are the 10" pram tube with bent valve and the 12" pram/kids bike tube with bent valve.