Since I bought my Time Capsule (only a few months ago) the AirPort Utility app has been changed/upgraded and the instructions that I got with the product on how to setup a guest wifi network no longer apply or make any sense.. So my question is how do I setup a guest wifi with apple's current software: Airport Utility v 6.0 on OS 10.7.4
The in app help will guide you if you search for guest or "set up a guest network"
The settings are under wireless with a simple check mark to enable a guest network.
Here is the most relevant steps from the help included with Airport Utility: