A new PSIO new firmware was released that fixes XA audio playback among other glitches: http://ps-io.com/news/
In order to update your firmware, you need to log into your account, then get the firmware from: http://ps-io.com/downloads/
Some people have reported new bugs with this firmware, as well as issues updating. The team behind it seems very responsive and is working on fixes for all. For more information, check out their forum: http://www.cybdyn-systems.com.au/forum/viewtopic.php?f=80&t=1143&p=14127#p14127
(thanks to FirebrandX for the pic!)
