Robert "Joe" Halderman Headed to Prison For David Letterman Extortion

David Letterman's extortionist did the crime, now he'll do the time.

Robert "Joe" Halderman, the former CBS News producer who copped to one count of attempted first-degree larceny, was sentenced today to six months in jail.

Money-grubbing mistress of David Boreanaz, take note.

Robert Halderman could've faced up to 15 years in lockup had the case gone to trial. Instead, his plea deal ensures he'll serve no more than the half-year term.

Manhattan Supreme Court Judge Charles Solomon also gave him four and a half years' probation and ordered him to perform 1,000 hours of community service.

Letterman blackmailer Halderman was snared in a sting operation.

The 48 Hours Mystery producer was busted in October for trying to shake down David Letterman for $2 million in return for keeping quiet about the comic's affair with his former intern and Halderman's then-live-in lover, Stephanie Birkitt.

Owing thousands of dollars in child and spousal support to his ex-wife, Halderman approached him under the guise of selling a screenplay ... to Dave's own life.

Rather than buying it to keep his liaisons a secret, Letterman blew the whistle, bluntly admitted on the air that he cheated on wife Regina Lasko, and moved on.

Halderman's moving on too ... to the big house. Nice work, man!