I have the same problem, but I rarely have sound for an hour. Most of the time it dies earlier. I use the ALSA-driver, because with OSS the game crashes on login. I tried to remove the libasound.so.2 from the libs directory, but that didn't help.
Computer
AthonXP 2000
512 MB ram
GeForce 7600 GS
Soundblaster Audigy
I'm using Debian Etch with the snd_emu10k1 ALSA sound module
Quitting the game wouldn't be a very nice option for me, because I lose sound after 5-10 minutes most of the time. It's not a real problem for me, because I can life without the game sounds, but it would be nice if someone had a hint how to solve this.
[Edit: added the name of the linux sound module]