I recently attended a brown bag on campus at the library, led by Dan Ream (aka "dream"). This one was on Selective Web Directories and I gotta tell you that it was really eye-opening. I didn't even know this stuff was out there, so thanks to Dan.
Click here for his page of great information.
The idea of a Selective Web Directory, as I understand it, is that someone has done the "weeding out" work that is required with a basic search on Google or Bing. This is especially helpful for scholarship, but it's also helpful for other narrow searches. I'm interested in using KidsClick with my son, for example. Cool to learn new stuff.