You all have heard of the anaconda bug wich causes i586 kernels to end up in i686 systems. There have been MANY workarounds, but not one that allows you to fix it before the installation. I think it's better to fix it before the installation, this also MIGHT solve some other problems.
The trick is REALLY simeple, when you insert the CD or DVD, type @ command prompt:
Want to check it? After the installation, open a console and type:
yum -d0 list kernel
You will see that the i586 is available for installation, but the i686 instead is installed.
This solution worked fine for me, any comments will be really appreciated