Ive managed to route sound output of planeshift to another alsa device then the default one, cause i have two soundcards and one sounds just crap.

1. apt-get/emerge/whatever latest libopenal0

2. rename /Planeshift/libopenal.so.0 to libopenal.so.0.tmp

3. symlink /usr/lib/libopenal.so.0 to /Planeshift/libopenal.so.0

4. choose openal in pssetup

5. create a file called .openalrc in ure home directory and add this lines:
(define devices \'(alsa))
(define alsa-out-device \"hw:1,0\" )
(define alsa-in-device \"hw:1,1\" )
(define speaker-num 2)

hw:1,0 / hw:1,1  <- of cause u have to choose ure prefered alsa devices.

btw. works quite similar for ut2004

bye