The Television producer accused of trying to extort David Letterman over the comic's sexual affairs pleads guilty.Robert ''Joe'' Halderman entered his guilty plea to attempted grand larceny Tuesday (3/9) in a Manhattan court.And later offered an apology.HALDERMAN says: "Just wanted to say that again I apologize to Mister Letterman, his family. To Stephanie Birkitt and her family. And certainly to my friends and family.Halderman is sentenced to six months in jail and one-thousand hours of community service.He was charged last fall with demanding two million-dollars to keep quiet about Letterman's love life.The case spurred the late-night TV icon to tell viewers he'd had affairs with women on his staff.