I can confirm these same results after the pulseaudio upgrade in Squeeze/Sid on 2.6.29 kernel. After updating udev, libudev0 and mdadm as per bug #548821 and this response in particular http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=548821#20 pulseaudio started working again. The sound servers were recognized and the Sound Preferences applet reappeared in my Gnome notification area. I did have to update my kernel to 2.26.30 series as per udev complaining that my 2.6.29 kernel was too old! I also had to restart my system for pulseaudio to respond to the changes. Hope this helps!
