Hi Ehsan,
With EIGRP, you can achieve load sharing if both paths to the same destination have the same best metric (equal-cast load balancing), or if the worse paths go through feasible successors and you configure the variance command (unequal-cost load balancing). In general, this is not trivial to achieve and may require a fair share of smart metric tweaking.
So the first thing to check is the output of the show ip eigrp topology table on the router with the two links (MPLS and P2P) and verify whether all destinations you want to load-balance for have at least one successor and one feasible successor identified. If yes then doing the load balancing is just a matter of activating the variance with a sensible value. If, however, the destinations only have a single successor and no feasible successor identified in the topology table then you will first need to start modifying metrics so that the neighbors first pass the feasibility condition and only then you can ask for load sharing.
I understand that this answer is just a very rough indication of where to focus your efforts, and is not a clean list of commands to apply to make the magic work. Tuning EIGRP metrics is not a routine task and it depends very strongly on your topology. What could perhaps help us suggest the more precise way of modifying your EIGRP metrics would be a listing of your show ip eigrp topology focusing on one particular network for which you'd like to achieve the load balancing. In that case please post the output of show ip eigrp topology X.X.X.X/M output so that we can see the component metrics in detail.
Best regards,
Peter
