When I try to go to http://public-yum.oracle.com/EnterpriseLinux/ I get error 404 (page not found). Anyone else having this issue?
Perhaps that is because the "EnterpriseLinux" part of your URL doesn't exist.
Use your web browser and `walk` backwards a bit along your link and go to http://public-yum.oracle.com/
You'll likely be able to read all the instructions there and get to wherever you need to be.
You did not specify what you are trying to accomplish but http://public-yum.oracle.com/repo/ is the root of the public yum repository. You can also check the content of the repo files listed at the main URL for info. However, keep in mind that browsing some of the directories is very resource intensive since they contain many files. Browsing the "latest" directories may not even be feasible and freeze your browser.
There is usually no need to browse the repo files as all available software can be listed and installed using the YUM utility, which is the standard, beside up2date since RHEL5. Using the RPM utility does not resolve software dependencies, in case this is what you have in mind.