The Scientific Method
Explaining How Science Works.

Ultimate Internet Science Guide
This has loads of goodies!

Free Online MIT Courses
Biology, Physics, History, Architecture, etc..

Evolution: Transitional Fossils
List of transitional forms

Evolution: Human Evolution
The transition from ancestral great apes to modern day homo sapiens sapiens.

Evolution: Observed Instances Of Speciation
Evidence Of Macro-Evolution

Dragon In My Garage
Carl Sagan