SINCE splitting with superstar girlfriend Mandy Moore, club staple DJ AM has been playing the field. Moore pulled the plug on their twosome last month, and spies have recently linked AM to model Jessica Stam, and he was spotted flirting up girls at New York clubs. Before he started dating Moore, sources told Page Six AM was looking for a "famous girlfriend," but now it seems an A-list name is not his main priority. "AM was really in love with Mandy," said one spy, "but they just had such different lifestyles, and they couldn't make it work."