Hi,
I did some googling and came across this:
http://moodle.org/mod/data/view.php?d=13&rid=928
https://launchpad.net/moodle-openid
which seems to have a version for moodle 1.9 that might be suitable.
There is also work ongoing to integrate Open ID support in Moodle 2.0. If that is successful that will become part of Totara when we release a verison based on Moodle 2.
http://tracker.moodle.org/browse/MDL-12903
Simon