GraspMath (Popularity: )
http://www.graspmath.com Provides interactive CD and video courses in Elementary Math, Algebra, Geometry, High School Exit Exam Prep, Trigonometry, Calculus and TI Calculators.
CatEdu (Popularity: )
http://www.catedu.com/ Developer of educational math and science software that uses animation to teach the basic concepts and principles.
MathWare (Popularity: )
http://www.mathware.com/ Mail order retailer of math software and graphing calculator books for high school and college.