• Official OpenGL site Contains lots of useful links from the basic to the fairly advanced levels.
  
  
• Mesa site Mesa provides a software emulation of OpenGL. This runs slower and often does not take advantage of your hardware's graphics capabilities. However, if your system does not have OpenGL, this is a good alternative.
  
  
• Good place for beginners This is another good page for step-by-step introduction to OpenGL.
  
  
• GLUT Links If you are using a PC at home or using another machine that does not have GLUT installed, you can download the GLUT pre-compiled binaries and documentation from here.