It's right in iTunes under the Advanced menu
AME and Compressor both have presets too.
Here is tech specs page (ipad 2 no different than iPad1 for specs)
http://www.apple.com/itunes/podcasts/specs.html#formattingvideo
Richard M. Harrington, PMP
Author: From Still to Motion, Video Made on a Mac, Photoshop for Video, Understanding Adobe Photoshop, Final Cut Studio On the Spot and Motion Graphics with Adobe Creative Suite 5 Studio Techniques