www.fedoratracker.org
gives a list of repositories for yum.
I would be a bit concerned about this setup, though. Obviously Fedora releases will come out every six months and there is a risk of breakages with each upgrade but presumably you can't upgrade versions yourself, so you need to know when the provider is going to upgrade even if they don't apply updates between versions.
I'm also a bit surprised that they don't run their own yum repository for updates at the data centre, rather than have their customers all chewing up bandwidth updating from different off-site repositories.