It is becoming more common these days for businesses, and even home users, to have multiple connections to the public internet either for load-balancing or fail-over functionality.
Unfortunately the routing protocol of the internet weren't really designed with this kind of usage in mind, so it requires a bit of trickery using Linux to get this working.
This script (written in perl) is designed to help get your iptables and iproute2 configuration setup to either fail-over or balance your traffic between 2 internet links.
Important: This script works at Layer 3 *only*. It balances connections, not individual packets. You can not setup link aggregation (ie, bonding) with this script.