I don't think doing an eye tutorial was a good idea....if you try to use this you'll probably just get confused. But people have asked me how did I draw eyes, so here it is.
I use the dodge tool set to "highlights" for the glowy effect, and the burn tool set to "midtones" for the shadows.
This tutorial was done for Photoshop, but I guss it could also work for other programs...as long as they have burn and dodge tools.
NOTE: file is HUGE