Kinderlose is a very simple plugin (which is good, because it’s a very small plugin): It removes posts from any possible child categories under a (presumed parent) category archive.
Inspired by Michael D. “mdawaffe” Adams’ Just One Category and Rich Hamilton’s No SubCats plugins, Kinderlose provides a WordPress 2.3 solution.
To download:
http://guff.szub.net/kinderlose/
