Gifted and Talented - D. Carlson

Pan Balance Problems
http://www.mathplayground.com/algebraic_reasoning.html

Solving Equations in Steps
http://mathsnet.net/algebra/l4_equation.html

Equation Jeopardy
http://www.quia.com/cb/77775.html

Algebra Four - try all levels
http://www.shodor.org/interactivate/activities/AlgebraFour/