Since the shader files can now be easily loaded ingame, lets collect some links and complete packs here.
http://www.minecraftforum.net/topic/940974-125sonic-ethers-unbelievable-shaders-glsl-shaders-dynamic-shadows-more/
http://www.9minecraft.net/tag/glsl-shaders/
Matmos
Water Shader
http://www.minecraftforum.net/topic/186241-modwinrenderer-wrapper-depthanglyph-colsnv-3d-vsnfs/