I've been learning the tutorials in a year or so now, and I can't go any further. Are you planning on developing more tutorials, or should I go and buy an OpenGL book?

buy books anyway, its sometimes quick to reference a book than trail the net for a simple answer.

Hi BBB, what is about tutorial #49 ?

The thing that helped me learn alot is to try to build something big
by myself and then search for specific topics that you need.

If you have learned everything in the tutorials is time to follow BlackRyders advice and start to make your own projects.
As you go along you discover things you don't know how to do, and then you can learn that spesific thing.

Good Luck.

Endre