According to http://www.oracle.com/us/corporate/press/1563775
• Effective immediately, Oracle will provide its Red Hat compatible Linux binaries, updates and errata for free.
If this isn't good news, I don't know what is.
I checked the the public yum repository files at http://public-yum.oracle.com and all of them have been updated. There is a new [xxx_latest] distribution channel, which is enabled by default. There are also additional channels for the UEK kernel and a "el5_unsupported" channel for Oracle Linux 5, which contains Openoffice, Evolution, etc.
So apparently what needs to be done in order to download and install the latest patches is to re-download the appropriate repository file and enable the appropriate channels you need.
Note: When downloading the new repository file, the wget command will not overwrite the existing .repo file - it will create an new one with .repo.1 filename extension. To avoid this, remove the existing repo file prior to downloading. E.g. "sudo rm -i /etc/yum.repos.d/public-yum*"