In GMing for Kids: An Actual Play Report, I mentioned that I wished there was more comprehensive advice available on this topic. Lots of GMs have kids, and assuming my future kids are interested in gaming, I’ll be curious about this myself before too long.
Katrina Middelburg-Creswell’s Role-Playing Games and Kids lays a great foundation — it’s full of practical tips, and it’s easy to tell that they come from experience.
If you have kids of your own, jump straight to the second half — the first section is about informing parents about gaming, and is more geared towards folks in a classroom or youth group setting (like Katrina’s previous article, Starting and Running a Role-Playing Games Club).
Good links on both counts — thanks, guys!