Update
Installing on 9.04 doesn't work, at least not without some substantial tweaking.
for starters some required libraries have been changed from 8.04 to 9.04, such as libgmp3 is now libgmp3c2 and Zimbra doesn't like it.
I'm now burning the Centos 5.4 DVD. Hopefully by the end of today I can give it go. I may need to start reading my Fedora Linux Toolbox book in order adjust to the command line difference
OK so back to 8.04. Centos didn't seem to like my hardware at all. It's such a tradeoff it seems, you either get corporate features from Red hat/Centos or you don't and get Hardware compatibility instead.