I've never used a mac, but in windows, there's a quick way to do this, and there might be a similar way in your mac settings. In the windows sound control panel, you can right click the pod go listed under playback devices, click properties, and there is an option to "listen to this device" and route the audio to your output of choice. However, this tends to have a ton of latency in my experience. This us likely due to the fact that this option probably doesn't take avantage of ASIO drivers for minimal latency, while any good DAW does. There are plenty of cheap or free DAWs that can easily do this. I'm pretty sure garageband supports ASIO drivers.
It would be nice if your monitors had another input. If not, another possible solution: buy or make a cheap A/B switch so that you can switch between your PC and POD Go to go to your monitor input. You might be tempted to use a Y cable to have both your PC and POD Go routed to your monitor input at the same time but do NOT do this. Your PC output would also be running into the POD Go output and vice versa, and running one ouput into another can be anywhere from bad to VERY BAD.
