Download xen-tools, install rpmstrap and install xen-tools. If there's a newever version of xen-tools available substitute that filename

yum install -y rpmstrap 
wget http://xen-tools.org/software/xen-tools/xen-tools-3.9.tar.gz
tar -xzvpf xen-tools-3.9.tar.gz
cd xen-tools-3.9/
make install

I've not using xen-tools that much but I wanted to put together a tutorial anyway. Let me know how it goes.