Here are some great sites that list iPad/iPod touch apps for physical education instruction
(Wordpress blogs may be blocked by some school filters):
http://thepeteacher.wordpress.com/2010/08/17/ipad-apps-for-physical-education/

The PE Geek Web site:
(Note: Swim Games app is NOT available in the US iTunes Store at this time.)
http://thepegeekapps.com/

USING IPADS IN PHYSICAL EDUCATION: THERE IS AN APP FOR THAT!

written by Joanne M. Leight and Randall Nichols, Associate Professors, Slippery Rock University
http://www.pelinks4u.org/articles/lleightNichols_1011.htm