Do I need to learn C++ to use Open GL?
OpenGL is a C API. There are bindings for other languages but samples in books and tutorials tend to be written in C.
Because of this knowing C can help. You definitely don't have to learn C++ to use OpenGL though.
Not necessarily. In fact, OpenGL is native C.
There is JOGL, which is a Java wrapper.
OpenGL ES, which is for the iPhone. I believe this is in Obj-C as well as C/C++. [Not sure, think so]
I think things like PyGame end up as OpenGL in the end, and they're done in Python.
But for raw OpenGL for the PC, the only choices I know of are C, C++, or Java.