Yes it's one of the joys of kittens. The other fun part is when they start their "homing devices" ie. they walk around miaowing all the time, presumably a survival mechanism so that Mum always knows exactly where they are. As I recall that lasts a couple of weeks and it's quite amusing while it lasts - at least it is until they start doing it when you're trying to sleep in the same room!
My girl is fostering a litter of 11 week olds at the moment (her own are almost 14 weeks and have left her now). She STILL follows them around calling them all the time. I've never seen anything like it!
Liz