Phil Bradley writes about using Squidoo to create teaching aids. It’s a “How to..” do anything social site with some cool features and a definite Web 2.0 feel.
Here’s his “lens” for web design: http://www.squidoo.com/webdesigning/
Here’s the lens for an “Intro to Web 2.0:” http://www.squidoo.com/introtoweb20/
UPDATE: More lenses from Phil: http://philbradley.typepad.com/phil_bradleys_weblog/2006/04/my_squidoo_lens.html