Your card has linux 3d drivers using DRI which comes with redhat9. I haven't used rh9 myself but I heard there is some option in the X configuration tool to enable 3d acceleration. Perhaps it is not enabled. Note that to use 3d acceleration on your voodoo3 X should run at 16 bit colors since a voodoo3 only supports 3d in that depth (and in some weird 22bit but that is not possible on linux ...)
If the game works it will look very ugly since the card doesn't support large textures and performance will suck. I recommend that you upgrade to some nvidia based card. (ati's linux drivers suck in ut2003)
Depending on your budget you can buy a (cheap: $75 ?) GeforceFX 5200 (Ultra) which is able to play ut2003 at an acceptable speed or upgrade to some better card like a Geforce4 Ti or a GeforceFX 5600 (Ultra).