start by checking the centos livecd project page; https://projects.centos.org/trac/livecd/
Well 5.10 livecd was not available, so I finally managed to build my own :)
excuse curiousness, why 5.1?
5.10 as I said. It has kernel driver to use my network card, so I can boot server with it and just copy os and datas from another machine..
-- Eero