Hi

This is what we have at some of our sites where we connect to an SP MPLS cloud.

Between CE1 and PE1 - EBGP

CE2 to PE2 - EBGP

PE1 -> PE2 - IBGP

We use MED (Multi exit discriminator) on our CE routers to influence how traffic routes into us. We advertise half our subnets out from CE1 and the same half on CE2 but with a different MED and vice - versa. This way you use both links for incoming traffic.

HTH

Jon