Some Perspective Papers:
• The future of secondary school geometry
• Justifying and proving in geometry
• The role and function of proof in mathematics
• Habits of mind: an organising principle for curriculum
• Alternative instructional strategies for geometry education
• Massachusetts curriculum framework

Some links:
• Connected Geometry
• Geometry and the Imagination
• The Geometry Junkyard
• The Geometry Centre
• Polyhedral Solids
• Polyhedra in the classroom
• World of Esher
  • Mathematical art of MC Escher
  • Mathematics and Art at Dartmouth College
• Tessellation tutorial (see especially Where's the Math in Symmetry)
• Geometry web discussion
• 27 proofs for Pythagoras
• The Divine proportion WARNING: you may be fascinated/shocked/offended . . .
• Graphics gallery
• Euclid's Elements All the books, and dynamic!
• Dynamic Java Applets
• Geobord activities
• Tangram activities