Seems the Oracle OVM team has provided updates for OVM 3.x through their public yum website. After previously running through hoops to ULN register your Oracle Linux systems, with a valid Customer Service Identifier, it is all public and free like things should be that are free.
In your OVM Manager 3.1.1, goto “Tools and Resources” and simply add the two urls.
YUM Base URL: http://public-yum.oracle.com/repo/OracleVM/OVM3/latest/x86_64/
* YUM GPG Key: http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el5