How to check OpenGL ?

[Bruno Costacurta]

Hello to All,

how to check if my video card (ATI Radeo X300) supports OpenGL 
and, if yes,  if OpenGL is installed on my Fedora Core 4 ?

I'm trying to install Second Life (a 3D simulation game by 
Linden) which is now available on Linux (still beta level) but it seems it 
needs OpenGL support. 
Following error code are received during startup :
...
INFO: createContext: window creation failure. SDL: Couldn't find matching GLX 
visual
...

Thanks,
Bruno