Some interesting excerpts from the article:
College baseball has had a few switch-pitchers in the past 15 years, but the major leagues have had only one since the 19th century: Greg Harris, primarily a right-handed reliever for many clubs from 1981 through 1995, pitched one inning using both arms for the Montreal Expos in his final season. That outing was considered more stunt than strategy.
A switch-pitcher facing a switch-hitter could make a fine Abbott and Costello routine. Against Nebraska last year, a switch-hitter came to the plate right-handed, prompting Venditte to switch to his right arm, which caused the batter to move to the left-hand batter’s box, with Venditte switching his arm again. Umpires ultimately restored order, applying the rule (the same as that in the majors) that a pitcher must declare which arm he will use before throwing his first pitch and cannot change before the at-bat ends.
Pics of him throwing each way:
There is also a video in the story page that you can view.