MPLS and VLAN info

I need to educate some coworkers (who aren't all that familiar with networks) and my boss on the security advantages of MPLS and VLAN's. I guess I don't seem to be communiating it very well because they just don't get it. Can anyone point me to some good technical docs that specifically deal with some of the benefints of MPLS and VLAN's. Specifically security related would help. TIA, Michael Long