well after dumping Ubuntu because of issues with the wifi i switched to fedora 10 at the request of a developer that i know swears by RedHat.
i am using a old laptop as media relay ( i plug it in the home theater) so that i can listen to XM Radio Online.
in UBUN it was not a issue because it worked from the start. in FC10 i could not get it to run.
well this is what i had to do .
check your sound settings make sure that the Hardware matched in the master preferences
now in the firefox. if you get stuck goto EDIT>TOOLs>Mediaconnetivty>Configure
now replace Windows media default with totem ( /usr/bin/totem )
also look for any other type of "streaming / mp3 " types and replace it with totem.
now when you start XM / Sirrus find your channel and punch it in then click on the icon and totem will start in a seperate window .. this will be a pain if you change stations alot but for long listing this is good . but keep in mind XM will toss you off after about 2 hour of playback..
hope this helps...