Integers
Here are some great sites for learning about integers:
Powerpoint Presentations
http://math.pppst.com/negatives.html
A list of more interactive sites:
http://classroom.jc-schools.net/basic/math-integ.html
http://www.mathgoodies.com/lessons/vol5/intro_integers.html
http://www.math.com/school/subject1/lessons/S1U1L13GL.html#sm1 (properties of integers)
http://mathforum.org/dr.math/faq/faq.integers.html (Dr. Math)
http://www.mathguide.com/lessons/Integers.html (Operations on integers)
http://amby.com/educate/math/integer.html (Integers: Operations with Signed Numbers)
http://www.bbc.co.uk/skillswise/numbers/wholenumbers/whatarenumbers/negativenumbers/game.shtml (Integer Game)
Games:
http://pbskids.org/cyberchase/games/negativenumbers/
http://www.funbrain.com/linejump/index.html
http://nrich.maths.org/public/viewer.php?obj_id=5911&part=index
Great videos:
http://www.youtube.com/watch?v=pc4r1Z2PwWo