In MatematicasVisuales we try to see mathematical concepts. If you want to learn more about the ideas involved you can find useful information in
It is a very big site about mathematics with visualization applications made using Mathematica.
The web site 'Cátedra UCM Miguel de Guzmán' has a lot of information about Miguel de Guzmán.
More applets:
Web site with a lot of pages and interactive applications about Mathematics developed by Alexander Bogomolny.
Excellent mathlets using GeoGebra.
Applets Java of Mathematics Walter Fendt Math Education and Technology  IES International Education Software Videos and mathematical animations: Cristóbal Vila, etérea estudios
Cristóbal Vila is an Spanish designer. He is producing spectacular 3D movies. He uses a lot of mathematics in his work and we can not miss them.
For example, Inspirations,
based on Escher's works, or
Nature by Numbers.
Complex functions: Tristan Needham  Visual Complex Analysis.
A wonderful book.
Frank Farris  Visualizing complexvalued functions in the plane
Farris introduces a new way to use color in visualizing complexvalued functions in the plane.
He has a very famous video about Moebius functions: Möbius Transformations Revealed.
Convergence: Where Mathematics, History, and Teaching Interact.
Convergence is the Mathematical Association of America free online journal about the history of mathematics and its use in teaching.
