In this documentation, it shows an example code:

class C(object):
    def __init__(self):
        self._x = None

    @property
    def x(self):
        """I'm the 'x' property."""
        return self._x

    @x.setter
    def x(self, value):
        self._x = value

    @x.deleter
    def x(self):
        del self._x

Which only runs on Python 2.6/3.0. This blog post demonstrates how to add the property.setter in Python 2.5.

I made a small change. The following code will check the Python version and replace built-in property with new one.

import sys
import __builtin__

# For Python 2.5-, this will enable the simliar property mechanism as in
# Python 2.6+/3.0+. The code is based on
# http://bruynooghe.blogspot.com/2008/04/xsetter-syntax-in-python-25.html
if sys.version_info[:2] <= (2, 5):
  # If you need to acces original built-in propery(), uncomment the next line.
  # __builtin__._property = property
  class property(property):

      def __init__(self, fget, *args, **kwargs):

          self.__doc__ = fget.__doc__
          super(property, self).__init__(fget, *args, **kwargs)

      def setter(self, fset):

          cls_ns = sys._getframe(1).f_locals
          for k, v in cls_ns.iteritems():
              if v == self:
                  propname = k
                  break
          cls_ns[propname] = property(self.fget, fset,
                                      self.fdel, self.__doc__)
          return cls_ns[propname]

      def deleter(self, fdel):

          cls_ns = sys._getframe(1).f_locals
          for k, v in cls_ns.iteritems():
              if v == self:
                  propname = k
                  break
          cls_ns[propname] = property(self.fget, self.fset,
                                      fdel, self.__doc__)
          return cls_ns[propname]

  __builtin__.property = property

This should make your code be compatible with both Python 2.5 and 2.6. Once decided to be 2.6 only, you will only need to remove the import statement. Actually, you don't have to if you are lazy. :-)