What routing protocol are you using?
EIGRP uses 'delay' as one of his metrics for calculating cost, so in this case you would need to assign either a cost or variance to do loadbalancing.
OSPF just uses the bandwidth statement so here you are OK.
BGP by default doesn't load share, you will need to use an IGP process to accomplish load balance.
Remember, you are only load balancing your outbound traffic, its up to your carrier to setup load balancing for your inbound traffic.
~rlc
