C++ and OpenGL resources:


OpenGL
Tutorial sites
Ultimate Game Programming
Almost as many useful programming tutorials as NeHe; but this also has sections on C, C++, the MS foundaction classes and Direct X
Neon Helium
NeHe; a *shit load* of good stuff here; check it.
CodeSampler.com
More advanced demo code, esp texturing tutes. DX, OpenGL, and others
Nate Robbins
You should know this place off by heart by now!
Flipcode
More general articles and tutorials; an awful lot of useful stuff buried away here.
GameTutorials
Well organised tutorials for C, C++, Win32 & DirectX, OpenGL and Networking. Due to a publishing deal, this site now requires payment for the older tutorials.
Zanir
OpenGl and DirectX tutorials; some material covered else where but a lot of unique stuff here too. Some source code commenting is in Polish; you have been warned!
The Code Project
Source code sample repository; not just graphics related.
Paul's Project
Tutorials for shadow mapping and simple Bump Mapping; w/source code


General sites
OpenGl related
The Geometry Junkyard
Home
OpenGL @ Lighthouse 3D - Docs

Sourcecode repository
SourceForge.net: Welcome
BerliOS Developer: Welcome

Interesting or useful code/programs
BerliOS Developer: Project Info - netPanzer
Magic Software: Source Code
SOLID - Software Library for Interference Detection
SourceForge.net: Project Info - GnuWin32
SourceForge.net: Project Info - win-bash
www.imagelib.org - DevIL - A full featured cross-platform Image Library
Xerces C++ Parser
The Code Project - System Tray Icons - Minimize Your Application to the SysTray - Shell Programming

Engines
Physics
Open Dynamics Engine
The Open Dynamics engine; an open source physic engine that can be integrated into most 3D engines. More or less ready to roll.
Newton Game Dynamics
Commercial physics engine.

Collision detection
OPCODE
Open source collision detection system for 3D system. Written in c++, it is free of charge for both private and commercial use.
RAPID -- Robust and Accurate Polygon Interference Detection System
Open source interference detect (collision detection) system, free for non commercial use. It is designed for use in "large environments composed of unstructured models", and is written in C++.
SOLID - Software Library for Interference Detection
A library for collision detection aimed principally at worlds written in VRML but also suited to OpenGL. Released under the GPL, it is also written in C++.

Sound
FMOD - music & sound effects system
Simple DirectMedia Layer
OpenAL

3D
Irrlicht Engine - A free open source 3d engine
Freeware game (graphics and physics) engine - C++ source code available.
IMR Terrain engine
A fully functional terrain engine with source code, written as a uni project.

Filesystem abstraction
PhysicsFS

Interface kits
ParaGUI

Game
The Yake Engine

Python

Code accelerators
Psyco - Home Page