You may want to try the sample yum.conf here:
That's what a lot of people use - just remember to copy your current yum.conf and back it up in case of problems.
Also, if you want a more intuitive interface, try GYUM, it's a GUI frontend and works quite well - just bare in mind that it takes a while to load up because it is scanning all of the repositories for updates.
The website says that you need a special version of YUM to use it, but it works fine with the stock version.
(If anyone can back me up or correct me on this, please do so.)