Gilder Lerhman, these guys rock
http://www.gilderlehrman.org/teachers/modules.html

Wiki, cause let's face it, you come here anyway.
http://en.wikipedia.org/wiki/Main_Page

Budget hero, actually kind of addicting
http://marketplace.publicradio.org/features/budget_hero/

Professor Patrick Rael's guide for writing at a collegiate level
http://academic.bowdoin.edu/WritingGuides/

How to cite stuff, with electronic help
http://sourceaid.com/

Very well done AP US History site
http://faculty.polytechnic.org/gfeldmeth/USHistory.html

Hippocampus, cause these guys use videos to teach
http://www.hippocampus.org/

Academic US History
http://sites.google.com/site/mrdubesacademicushistory/home

Revolutions
http://sites.google.com/site/mrdubesrevolutionsclass/

Really good set of notes that cover similar chapters to out book.  They do not match perfectly but they are decent.
http://wikinotes.wikidot.com/13th-edition