I installed Quake 3 using an ebuild (Gentoo), and everything wne tinfe.
Then i tried to run it and get

...loading libGL.so.1:
Calling SDL_Init(SDL_INIT_VIDEO)...
SDL_Init(SDL_INIT_VIDEO) passed.
QGL_Init: Can't load libGL.so.1 from /etc/ld.so.conf or current dir: No dynamic GL support in video driver
failed
----- CL_Shutdown -----
RE_Shutdown( 1 )
-----------------------
----- CL_Shutdown -----
-----------------------
Sys_Error: GLimp_Init() - could not load OpenGL subsystem

I have the Gentoo kernel module enabled and working (glxgears works great), and it is set to driect renderring.
I made sure i had this enabled and the dri module turned off when starting Xorg (just to test, had the NVIDIA logo show up), and default depth is set to 24 in xorg.conf

I've even tried symlinking libGL.so.1 to /usr/lib/opengl/nvidia/tls/opengl.so.1.0.7676 and /usr/lib/opengl/nvidia/lib/libGL.so.1 and run ldconfig after each one and still no go.
Oh, and both /usr/lib and /usr/lib/nvidia are in /etc/ld.so.conf, and running lconfig -v verfies that it is looking at this properly.

So, whats the issue? I also tried Nexuiz and Quake2 and nothing will find this library. Where is it and why is it not being loaded through ld.so.conf properly? I have updated/downgraded to different kernel versions (and associated libraries) and nothing.

Running on a P4 2.1GHZ, 512MB, NVIVIA GEFORCE4 256MB

I had the same problem yesterday. Mine was solved like this: I executed quake 3 with additional parameters:

tiuri@tiuri$ quake3 +set r_gldriver libGL.so.1.0.7676

... and it worked. Hope this helps