I don't know if you want to arbitrarily use local-pref and AS-Path prepend in a one-size-fits-all approach, as under certain scenarios it might be more beneficial to route traffic between POPs to take advantage of routes via shortest AS Path or other constraints. Why not just extend your IGP across all POPs and set inter-POP links to a higher metric? In this scenario, if a given route is received via muliple POPs and all things being equal (AS Path, etc.), you'll prefer to route traffic out the shortest-cost path to a POP exit point.
Sorry for the top post, I'm on my BB.
Stefan Fouant
Neustar, Inc. / Principal Engineer
46000 Center Oak Plaza Sterling, VA 20166
Office: +1.571.434.5656 
Mobile: +1.202.210.2075 GPG ID: 0xB5E3803D stefan.fouant@neustar.biz
I don't know if you want to arbitrarily use local-pref and AS-Path prepend in a one-size-fits-all approach, as under certain scenarios it might be more beneficial to route traffic between POPs to take advantage of routes via shortest AS Path or other constraints. Why not just extend your IGP across all POPs and set inter-POP links to a higher metric? In this scenario, if a given route is received via muliple POPs and all things being equal (AS Path, etc.), you'll prefer to route traffic out the shortest-cost path to a POP exit point.
Sorry for the top post, I'm on my BB.
Stefan Fouant
Neustar, Inc. / Principal Engineer
46000 Center Oak Plaza Sterling, VA 20166
Office: +1.571.434.5656 Mobile: +1.202.210.2075 GPG ID: 0xB5E3803D stefan.fouant@neustar.biz
I agree with Stefan. You are better off extending your IGP across PoPs as it will give you more flexibility in the long run. If you ever want to go down the path of traffic engineering / MPLS / etc, you will find it much easier as this will allow for CSPF and multi-topology routing architectures.
Truman