The free 3D modeler Blender has some functions for creating 3D text.
You can also import your own font.

Drawing text with OpenGL is challenging, it isn't built into the specification. I would suggest looking for a 3rd party library for rendering text with OpenGL ES.

OpenGL is designed for rendering 3D objects (typically models built out of triangles), not 2D primitives like circles and rectangles. You can render a plane object and texture it with whatever you like, but that isn't quite the same.

- Kim