ALO Audio's new headphone amp is a single-ended and balanced headphone amp that features a 24/96kHz USB DAC for plug and play with your computer and with certain iOS devices. Of note, any iPad should work out of the box with the right adapter. I use the 30-pin to USB iPad Camera Connection Kit.
Jailbreakers: Big Boss Camera Connector is available for 99 cents from Cydia. Plug in the Apple iPad Camera Connection kit and a USB cable and voila! your pre-iOS 6 devices will work without hitch. I've had trouble getting any non-iPad iOS 6 device working with Apple's Camera Connector. Big Boss doesn't seem to help. If you are on an iOS 5 device, The International works without hitch.
More about Big Boss Camera Connector here.
Follow the headfi thread for impressions and reviews.
NOTE: ohm-image did not take the wonderful images seen on ALO's webpage.