Starfall (learning letters and sounds) http://www.starfall.com
PBSKIDS (learning games that include shows that can be seen on PBS) Sesame Street, Barney, Between the Lions, ect) http://www.pbskids.org
StoryPlace (tells simple interactive stories for preschoolers) http://www.storyplace.org
Literacy center (Very simple games) http://www.literacycenter.net/lessonview_en.htm#