After a call has connected, you can press the rec button, and iPhox will begin recording the call. The file is placed by default on your desktop, but you can specify a location in your software options/preferences. The file is a .wav file and should be playable from any media player like Quicktime or Windows Media Player.
When you begin recording the call, the other party will hear an announcement, "Call being recorded." You will not hear the announcement. When you finish recording, the announcement will tell the other party, "Call recording stopped."
Recording calls is legally restricted in certain countries, states and localities around the world. It is your responsibility to understand and comply with any laws that may apply to you or the person you are calling.