www.opengl.org/developers/documentation/glut/index.html
The GLUT pages at www.opengl.org.

www.mesa3d.org
The Mesa website.

www.loria.fr/projets/SmallEiffel
SmallEiffel's website.

OpenGL Programming Guide, Third Edition, The Offical Guide to Learning OpenGL, Version 1.2 by M. Woo, J. Neider, T. Davis and D. Shreiner. ISBN 0-201-60458-2 (1999). This book is often referred to as "the red book". It is a must have, if you want to do OpenGL programming.

Computer Graphics Using OpenGL, Second Edition by F.S. Hill, ISBN 0-02-354856-8 (2001). Is a good book on the principles and basics of computer graphics and all the examples in the book are based on OpenGL.

OpenGL Superbible: The Complete Guide to OpenGL Programming for Windows NT and Windows 95 by R.S. Wright and M. Sweet. ISBN 1-571-690735. (1996). The title says it all. Probably one of the best books available on programming OpenGL on Windows platforms. (There exists a newer edition of the book today).

The OpenGL Utility Toolkit (GLUT) Programming Interface (API Version 3) by M.K. Kilgard. (November 13 1996). Good concise documentation on GLUT from the horse's mouth. It can be found at the GLUT pages listed above.