At this point there is no way to listen to XM/Sirius on Android devices. They have to publish an Android app in the Market or someone has to find a way to stream the web feed to an android device. Sorry
Actually I use a program called ORB along with a plugin called uSirius. It is a bit complictaed, but does work. The difficult part is finding uSirius. Not readily available, but with some searching it can be found. Setting it up is a bit technical also. But it can not only listen to my Sirius account, but also tap into the TV tuner in my PC and watch my DirecTV.. If you go to www.orb.com, yyou will understand what it does.