By Yereth Rosen

ANCHORAGE, Alaska (Reuters) - A Pennsylvania man will be sentenced to five years of criminal probation after he pleads guilty to harassing the family attorney of former Alaska Governor Sarah Palin, under a plea agreement filed on Tuesday.

Details on the plea deal were provided in court filings in U.S. District Court in Anchorage in which Shawn Christy, 20, said he would plead guilty to making harassing telephone calls to Palin's Alaska attorney, John Tiemessen of Fairbanks.

Under other terms of the plea deal, Christy would not "communicate in any manner" with any individual in Alaska other than his defense attorney, absent court permission.

The court papers said Christy's criminal probation would be served in his home state of Pennsylvania, and that he must complete a mental treatment program in either an inpatient or outpatient setting.

He would also be barred from possessing a computer or cellular telephone with online access and from using computers in public facilities, terms that could be modified by the court or by his probation officer.

Christy, 20, and his father, Craig, were accused of making at least 500 hostile and threatening phone calls to Tiemessen and the attorney's colleagues, according to court documents.

The calls, made "repeatedly and continuously," came mostly between August 1 and August 9, according to the plea agreement. Shawn and Craig Christy were arrested in Pennsylvania later in August. They were ultimately sent to Alaska and have been held since then in jail in Anchorage.

Shawn Christy was scheduled to officially enter his guilty plea and be sentenced later this month under an order issued by the judge in the case, court papers said.

A plea agreement was also expected from Craig Christy, 48, according to court papers filed earlier this month.

The felony charge of making harassing interstate telephone calls carries a maximum penalty of two years in prison and a $250,000 fine, Assistant U.S. Attorney Retta-Rae Randall said on Tuesday.

Both men were already the subject of restraining orders issued by an Alaska state court over repeated telephone calls that authorities said they made to Palin's parents and her longtime friend, Kristan Cole.

Palin first won a restraining order against Shawn Christy last year. In a court hearing this year, she described him as being obsessed with her and said he made sexual threats.

In May, the state court issued a new restraining order against Shawn Christy and a similar order against Craig Christy over calls he made to the Palin camp.

(Editing by Alex Dobuzinskis and Cynthia Johnston)