We will be implementing an MPLS network over private ports that will
join 4 remote offices.  Our plan is to have video conferencing units
in each location.  The units will be used once or twice a week at
most.  We would like to have the option to add VoIP at a later date.

I'm a little confused about where we will need to configure QoS.  The
provider will configure The new MPLS edge router for QoS.  Will I need
to configure QoS on all switches in my environment?

Here's a diagram of the main office location where the servers will be
located. The other offices have a similar but much smaller design.

                400 workstations, Video Conference Unit
                                 |

                11, 48 port Cisco 3750 GigE
                                 |

                Cisco 6509  w/ SUP2, PFC, MSFC
                        /                       \

Cisco MPLS Edge Router          Juniper Internet Router
          |                                                |
MPLS Newtwork                             Internet

Will QoS need to be configured on the Cisco 3750's as well as the
6509?

Any information would be appreciated.