Quaternions in OpenGL

Do you know any good Quaternion in OpenGL tutorials ?
Or could you post some code here ?
I found some on gamedev.net but I’m interested to in SLERP and other stuff.

I have done some quats in c on the mac for opengl.
What do you want the tutorial for? Understanding quaternians or applying them?


Whele ,I found a great article at gamasutra with soirce code.
So rather understanding them.

How good is your vector math, i.e. normals, planes etc? The concept of a quaternian is pretty simple, possibly simpler than matrix rotation. And the whole point is that they are quicker as to apply a rotation using a quaternian takes less operations than using a mtrix, in some apps this is very important as there are many rotation calculations