As explained in /usr/share/doc/udev/NEWS.gz (version 148), BUS has been deprecated in favor of SUBSYSTEM and SYSF has been deprecated in favor of ATTR. The patch attached eliminated the warning messages on my system.
I wonder, by the way, if this should be fixed upstream. http://svnview.digium.com/svn/dahdi/linux/trunk/drivers/dahdi/xpp/xpp.rules, currently at revision 7595, is using the deprecated syntax.
--- dahdi-linux-2.2.0.2~dfsg/drivers/dahdi/xpp/xpp.rules 2009-04-02 15:27:42.000000000 -0500 +++ /etc/udev/rules.d/xpp.rules 2009-12-24 14:15:37.000000000 -0600 @@ -1,9 +1,9 @@ -BUS!="usb", ACTION!="add", GOTO="xpp_usb_add_end" +SUBSYSTEM!="usb", ACTION!="add", GOTO="xpp_usb_add_end" KERNEL=="*_ep*", GOTO="xpp_usb_add_end" KERNEL=="[0-9]*", GOTO="xpp_usb_add_end" # Load firmware into the Xorcom Astribank device: -SYSFS{idVendor}=="e4e4", SYSFS{idProduct}=="11[3456][01]", \ +ATTRS{idVendor}=="e4e4", ATTRS{idProduct}=="11[3456][01]", \ RUN+="/usr/share/dahdi/xpp_fxloader udev $sysfs{idVendor}/$sysfs{idProduct}/$sysfs{bcdDevice}" LABEL="xpp_usb_add_end"