In order to update your packages on CentOS via YUM, do the following:
- Edit /etc/yum.repos.d/CentOS-Base.repo
- Set enabled=1 under the section [centosplus]
- Finally, do "yum update" and it will scan the repository and ask you if you wish to upgrade your current packages.
I used this to upgrade mysql to 5.x and php to 5.x! W00t!
