Yes! While recording in Capture with the iOne or iTwo, you can hear your recording through standard 3.5mm headphones plugged into your iPad's headphone jack. The audio from your i-series Audiobox will be transferred to your headphones instead of the outputs on your iOne or iTwo.
If you plug in headphones with a built in microphone, you will now be able to record from the headphone mic instead of the iOne or iTwo inputs. You will also hear all audio through your headphones as stated above.