It prints out a number of things like the file system and name, im not sure if it has the serial number but thats what other people on the python mailing list thought that it might be. So give it a shot. For this you need the Mark Hammond modules for windows. That includes the win32api http://starship.python.net/crew/mhammond/win32/Downloads.html
Hope that helps. If not have a bit of a google yourself. :) Just to check
returns tuple containing ...
string - name of volume/disk/drive
long - serial number of volume/disk/drive
long - maximum component length of a file name
long - flags specific to the file system
string - file system name
path = "C:/"
info = win32api.GetVolumeInformation(path)
print( "disk serial number = %d" % info )
my output on Vista machine -->
disk serial number = 1022625589