Two years of planning already has gone into the year-long celebration of the 250th birthday of George Washington, Fairfax County's famous resident and the country's first president.

The celebration won't begin until 1982, but the George Washington 250th Birthiday Celebration Commission -- established by the Fairfax County Board of Supervisors in 1978 -- is working on coordiante efforts of other groups and institutions, assist those who want to plan activities, gather information about celebrations planned outside the county and stimulate interest in George Washington and Fairfax County history.

The commission, chaired by Toni McMahon of the Mount Vernon Citizen's Association, has proposed that the celebration focus on 12 aspects of Washington's life. Community groups and county government agencies are encouraged to send in announcements of any activities they are planning, so they may be included in a regularly updated calendar. Events to be included in the next calendar may be sent to GWBCC, 8101 Hinson Farm Rd., Suite 113, Alexandria, Va. 223608. The deadline is Dec. 15.

A series of U.S. postage stamps to commensurate the anniversary are being proposed by the commission and the Mount Vernon Ladies' Association. In addition, the commission has plans for a commemorative medal and souvenir items that would be sold in 1981 and 1982.