Rob (and Sjonny too): Multitexturing functions is not found in any library file, since they are implemention-specific. You must load them yourself, using wglGetProcAdress(char *ext), where ext is the name of the function you want to load. It can seems to be a tad difficult, but is actually not that hard.
Here are a way to go:
Go to nVidia and get a headerfile with all extensions (works fine for all manufacturers).
Include the file and declare functionpointers.
Assign each functionpointer a value.
Now you can call glMultiTexCoord2fARB.
PhilipT: Yepp, Q3A (aswell as any OpenGL-based game) will run (ALOT) faster with a GeForce. Why? Because Q3A calls native OpenGL-functions, and all OpenGL-functions is loaded (when you start Windows) from the current driver you have installed. If your drivers can perform function X in hardware, each call to X will be performed in hardware. If your driver does not support hardware, X will be run in software (since this is how X is written by the manufacturer).