This lesson uses the diamond method to factor quadratics. It has a nice document with a lot of good problems that are ready to use. I have been experimenting with the diamond method after attending a workshop last year. I have found that it provides structure that the students can always fall back on if they have difficulty factoring. I try to give a variety of options for students to use when factoring and encourage them to look for shortcuts (we call it guess and check). It also has some problems that connect factoring to algebra tiles. If you are getting ready to cover factoring in your algebra class I would recommend taking a look at this document.
This lesson has a lot of nice problems using the box and diamond method for factoring that ties it in with algebra tiles. In my classes I use a modification of the box and diamond method and have had pretty good success in getting my students to learn how to factor and retain what they have learned. This is a definate consideration if you are teaching a unit on factoring.