WIDE AREA NETWORK SETUP

How can i enable a current client site that has a WAN spanning 7 remote sites covering two countries, to utilise and load balance two different link providers so that they can achieve a load balancing between the links as well as have no downtime should one link go down as the other link continues serving.

They are currently on the local Telcom’s 64k leased line, but have also gone for a satelite link with one of the local providers on 64k as well.I can’t get both working in cohesion even when i put costs on my ip routes, and this lines will only function on their own.Please advice as the cleint is paying for both links on a per month basis.