I have slackware 10, kernel 2.6.8.1. What i did was that when I recompiled my kernel, I took off ALSA support but enabled Sound support. After that I then downloaded the latest alsa driver and other things it needed from alsa-project.org and recompiled it for my system.
As for the LAN thing, if you go to
http://zerowing.idsoftware.com/linux/doom they tell you how to do it.
Im running Doom3 on an low end system. AthlonXP2000, 512mb ram, FX5200 128mb, and it runs much smoother than in Windows XP.. (i had slack installed and configured, deleted it all for Doom3 on windows XP the other day, and then i came back to Linux today when I found Doom3 for linux)..
For me, doom3 on linux runs much faster than on WinXP (optimized and tweaked, and video card OC'd of course).. On linux my average fps on the part where you first receive your PDA is around 40 fps.. on WinXP that was on 30fps.. But when I first ran Doom3 on linux, i was getting 10-14 fps.. And then I did some tweaking on the config files for Doom and found out that it was using a f'd up renderer for Doom3.. The r_renderer was on "best" and i was getting crappy fps.. Since i have an FX5200 which is supposedly an NV34 chip, i used that for the renderer and then I still crappy fps and now a crappier look..makes me go hmmm..maybe i got a bad card and or drivers eh? (it shouldnt be because my 3d app i use and quake3 runs fine).. I then changed that setting to NV20 and wowza, now things look good and smooth. =)
My settings on Doom3 are on Medium Quality so im pretty happy.
though i really want to upgrade to play it super ultra high settings hehehe.. ok back to Doom3 i go! time to get scared like MESH! :P