[ALUG] Linux for kids for XMAS...

Hello again, My sis and a friend of hers are looking to buy PC & printer for use by "the kids" for XMAS. When I say kids, we're talking the 4+ age group. Obviously the adults will want mail, web, office, etc. but nothing too daunting - thought I'd ask if anyone has hardware + distro recommendations. We're talking easy-to-use once installed and cheap solution.... however I was thinking mini-ITX cases etc. Any ideas? I want to give them a good base to learn from ;) Steve p.s. thought I'd ask on here as still pretty lonely in LUGE at the mo... but it'll get there in time...