NCTM Geometry Standard for Grades 6-8
Use repeated execution of Edit/Find... to find "software".
There are many dynamic geometry software suggestions in these
standards.

Lesson Plans Using GSP For Grades 6-8

http://www.yrbe.edu.on.ca/~cecw/docs/software/guides/GEOACT.PDF
Geometry Activities for Middle School Students with The Geometer's Sketchpad.
The text and cd can be purchased at http://www.keypress.com/sketchpad.
They are still working on upgrading this text to Sketchpad 4.

http://mathforum.org/sketchpad/sketchpad.html The Geometer's Sketchpad
Math Forum Classroom Resources

http://mathforum.org/~annie/gsp.handouts/
Annie's Sketchpad Activities

http://mathforum.org/sketchpad/littleones/ Sketchpad for Little Ones

http://www.occdsb.on.ca/~tec/gsp.pdf
A Collection of Useful Information for Teachers Wanting to Learn Geometer's
Sketchpad. Includes suggestions for assessment.