Here are two great websites to search for the 5th Grade Colonies Project:

America's Library:
http://www.americaslibrary.gov/search/search.html

Grolier Online Library
http://go-passport.grolier.com/splash

USA History
http://www.usahistory.info/

Social Studies for Kids, click on your state name
http://www.socialstudiesforkids.com/subjects/usstatescolonies.htm

Kid Info (this site links to many of the above sites)
http://www.kidinfo.com/SchoolSubjects.html#AmericanHistory