If you're going to go the route of OpenGL, there are really two suggestions, depending on what you're interested in. I'd personally go with OpenGL 3, because I'm cool like that, but OpenGL 2.x will still give you access to the fixed-function pipeline.
If you need a learning resource for it, I recommend Beginning OpenGLĀ® Game Programming, Second Edition (ISBN 978-1-59863-528-7) by Luke Benstead.