This is the latest orange (shaders) and red book (programming guide) combined. This latest version has again become a good beginners (and beyond) tutorial on OpenGL 3+.
The book has a website with links to a lot of related material including other schools using the text.
This is an excellent tutorial book which covers labs as well as more advanced material. Programming examples are available from its' website.
This is the programming guide tailored to OpenGL ES 3.0. OpenGL ES 3.0 is the mobile version of the API but also runs on the desktop. See the accompanying website.
This is the programming guide tailored to WebGL 1.0. WebGL 1.0 is based on OpenGL ES 2.0 and feels a bit dated now but direct browser display is still cool. See the accompanying website. WebGL 2.0 is already available as a specification and is now based on OpenGL ES 3.0.
This (the orange book) is also a very good tutorial book which covers labs and beyond. Programming examples used to be available. Now somewhat dated (Open GL 3.1) but topics are still of interest.
The official OpenGL website with all kind of information: books and other documentation, coding resources including examples, job postings etc.
Collection of step-by-step tutorials starting with the basics in OpenGL 3.3 (some require 4.0).
On-line book by Jason L. McKesson with examples in OpenGL 3.3.
Excellent collection of tutorials on a wide range of topics but mainly for the fixed pipeline.
Advanced C++ Programming.
C++ reference and more.