Tom Cruise has already claimed to know the history of psychiatry. Now he's working on getting acquainted with OB/GYN. The couch-jumping thesp has acquired a sonogram machine with which to personally track the progress of the fetus currently incased in his fiancee Katie Holmes' womb. Cruise revealed the purchase during an interview with Barbara Walters taped Oct. 30 for the veteran newswoman's upcoming special, Barbara Walters Presents: The 10 Most Fascinating People of 2005, scheduled to air Tuesday on ABC. "I bought a sonogram machine," Cruise told Walters. "I am going to donate it to a hospital when we are...