AT&T Communications of Virginia Inc. has relocated its operations to the Flint Hill Office Park, a 48-acre site at the intersection of Routes 66 and 123 in Fairfax.

The telephone company will occupy the entire eight-floor, 160,000-square-foot building, which is the third building in the park. The long-term lease has a value of about $28 million, according to Julien J. Studley Inc., the agent in the transaction.

Three Flint Hill, as the building is called, was developed jointly by the Lerner Cos. and Mar Kap Enterprises.

Central Plaza Construction Co. recently began construction on a 4.7-acre shopping center on University Boulevard in Langley Park. Developed by Pan American Associates for the area's Hispanic-American community, the Plaza will assist foreign entrepreneurs in finding suitable retail space and is expected to create 200 to 300 jobs, according to the Prince George's County Economic Development Corp.

Other recent developments in commercial realty:

* AT&T Resource Management Corp. has subleased 23,947 square feet of office space on the eighth floor of the Fairchild Building at 499 South Capitol St. in Washington to the U.S. Postal Service's Employe and Labor Relations Group.

The postal service employes were displaced from their headquarters at L'Enfant Plaza when a fire destroyed much of the top two floors there.

* Tiber Construction Co. has begun construction on the Executive Office Center at the intersection of Executive Boulevard and E. Jefferson Street in Rockville.

The 230,000-square-foot office building is expected to be completed by September.

* USA Today, the national newspaper published by Rosslyn-based Gannett Co. Inc., has leased 4,100 square feet in Tech Center II in the Inglewood Business Center in Prince George's County to serve as a circulation office. The building will house 20 employes.

* First American Bank of Maryland recently opened its Prince George's County headquarters at 9201 Basil Ct. in the Inglewood Business Community.

* The Institute for Defense Analysis, a federally funded organization that conducts research for the Defense Department, has leased 28,791 square feet at 5 Skyline Place, the most recent addition to the Skyline Complex at Bailey's Crossroads.