Preschool Curriculum

I asked my friend what preschool curriculum/sites she recommends. This is the list she gave me:

http://www.mothergoosetime.com/ (more bang for your buck, with little to no assembly time)

http://www.preschooleducation.com
http://www.preschoolprintables.com
http://www.starfall.com
http://www.preschoolrainbow.org (great for supplementary curriculum ideas)
http://lessonplanz.com/Preschool/
http://www.preschoolbystormie.com/
http://www.letteroftheweek.com/

Good place to buy workbooks:
http://www.kumonbooks.com/home/wheretobuy_retail.aspx

I am planning to do preschool with the boys and my youngest daughter, I'm actually considering a light version for the summer months, since I will continue with my oldest daughter and her reading.