[CentOS] Building a 64bit rpm

>Use yum to install rpmdevtools.  Then rpmdev-setuptree will do all of the work
>that's required to build rpms as a user.

Frank,
So reading through all of this, it looks like the rpmdevtools from epel is the simplest. Once I create a non root user, then as that user create the build environment, where should I execute the `rpmbuild --rebuild xen.srpm` command from? I assume that matters so the rpmbuild command finds whatever file it needs to work under the fake root?

Just to clarify, if I am on an x64 system, will this only create the x64 rpm as expected?

Thanks!
jlc