sudo yum install @virtualization
change selinux to disabled
/etc/sysconfig/selinux
well, basically do this: http://wiki.xen.org/wiki/Fedora_Host_Installation
Also if your virtbr device is there and causing problems
From http://www.cyberciti.biz/faq/linux-kvm-disable-virbr0-nat-interface/
# virsh net-destroy default
# virsh net-undefine default
# service libvirtd restart
# ifconfig