http://nlvm.usu.edu/en/nav/vlibrary.html National Library of Virtual Manipulatives
http://illuminations.nctm.org National Council Teacher Mathematics (NCTM) Illuminations Illuminations is designed to Provide Standards-based resources that improve the teaching and learning of mathematics for all students. Provide materials that illuminate the vision for school mathematics set forth in Principles and Standards for School Mathematics. Illuminations is part of the prestigious Verizon Thinkfinity program.
http://onlinestatbook.com/rvls/index.html Statistical Analysis Manipulatives from Rice Virtual Labs
http://highered.mcgraw-hill.com/sites/0073022845/student_view0/virtual_manipulative_kit.html Virtual Manipulatives Kit This updated Virtual Manipulative Kit can be conveniently accessed and moved about the screen. Each of the nine manipulatives has a work area with toolbar to display manipulatives and a notepad for recording data and results. Both the notepad and the work areas can be printed to turn in for assignments or projects