Oswego City School District
Regents Exam Prep Center: Multiplying Binomials
Explains five methods for multiplying binomials: (Distributive Method, FOIL Method, Vertical Method, Grid Method, and Using Algebra Tiles).
National Council of Teachers of Mathematics
The Math Forum: Understanding Algebraic Factoring
This site from the Drexel University explains the principles of factoring symbolically using algebra tiles.