No, the ASA can't terminate MPLS. But are you sure that you really need that? From a customer-perspective, the link to the MPLS-provider-router is a pure IP-link. So you can connect your ASA to an MPLS-provider in that way.
Do you mean can an ASA act as a PE device, ie. it supports MPLS labels and MP-BGP for the VPN routes, then as far as I am aware this is not supported.
If you mean can it act as a CE device running BGP and peering with a PE router then yes because that is just a standard BGP connection and BGP support was added in version 9.2(1) of the software.
Edit - sorry Karsten, didn't see your reply.