I thought this was quite a good blog post. Crispy Gamer has
10 no bullshit rules for non-gaming parents to follow when buying computer games for kids. As s/he says, there are a lot of rubbish games out there, but also some gems. Why not buy good games if you're buying games at all? He has a list of
25 recommended games for kids too.
edited to add: sorry, link fixed.