CosmoNet http://www.thinkquest.org/library/lib/site_sum_outside.html?tname=27930&url=27930/
An "interactive book" focusing on the topics of astronomy, cosmology, and theoretical physics. It also provides a number of services including an index of all 88 constellations, several interactive games and quizzes, and extensive information on stars, galaxies, and the Big Bang.
Introduction to Cosmology http://arxiv.org/abs/astro-ph/9312022
These notes form an introduction to cosmology with special emphasis on large scale structure, the cmb anisotropy and inflation. In some places a basic familiarity with particle physics is assumed, but otherwise no special knowledge is needed.
The Cosmology http://library.thinkquest.org/28181/
This educational site is designed for people of high school age or older who want to understand the most recent information about cosmology in everyday language.