Solving Simple Equations
This is an interactive site with solving some simple equations.
http://www.majormath.com/prealgebraequsimp.htm

This is a nice series of simple step-by-step examples for solving simple equations.
http://regentsprep.org/Regents/math/solveq/LSolvEq.htm

Addition and Multiplication Properties of Equality
This site includes some examples of solving equations using the addition (or subtraction) property of equations.
http://library.thinkquest.org/20991/alg2/eq.html?tqskip1=1&tqtime=0323