Hi Rob,
Possible solutions depend on what you want to achieve. Some ideas on this:
1) host name load balancing: if you want to make your (web) service highly available or increase its nwk througput, then you can give each of your NICS its own IP address (not even necessarily in the same subnet) and have your network translate your hostname or URLto any of the IPs, f.e. in a round robin fashion. DNS load balancing is not sophisticated, though, for it cannot check the availability of your NIC. To improve this kind of solution you would need a load balancer appliance in your network. hostname or URL based load balancing I would refer to as L3 (OSI layer 3) load balancing.