Michael Phelps appeared on Conan last night. Phelps just competed at the U.S. National Championships, where on Thursday he broke the world record in the 100-meter butterfly.  His performance qualified him for the world championships in Rome airing Sunday, July 26, Saturday, August 1 and Sunday, August 2 (12-2 p.m. ET) on NBC.  Phelps talked about getting back into the water after his 6 month layoff and his recently released children’s book HOW TO TRAIN WITH A T. REX AND WIN 8 GOLD MEDALS.