GENERAL GEOMETRY
A popular geometry site with a lot of information about all sorts of geometrical stuff.
Interactive Geometry Classroom Resources
A web page with a lot of interactive geometry programs, including tonnes of interactive geometry programs.
A web page featuring a good deal of interactive Java applets for exploring geometrical issues, such as 3D shapes, 2D shapes, nets, transforamtion, etc.
TYGH Animated Proof for Pythagoras' Theorem
Interesting proof of the Pythagoras Theorem.