Let's make a thread here of the sites we've used and found helpful in our homeschooling. Here's a few to get started:
http://www.letteroftheweek.com/ (online preschool curriculum)
http://www.edhelper.com/ (printable worksheets)
http://www.littleexplorers.com/school/ (Enchanted Learning)
http://www.amblesideonline.org/ (online Charlotte Mason curriculum)
http://www.zionfriedheim.org/acceler...%20letterO.htm (accelerated reader booklist to tell you what grade level different books are)