With sound trucks and phone banks and thousands of leaflets and posters, campaigns for the Washington School Board have moved into the last days before Tuesday's election.

Even though voters throughout the city will be able to fill two at-large seats on the board, the most spirited contests are taking place in the five wards - two, three, four, seven and eight - where board representatives are being chosen.

In ward four, for example, main streets are festooned with posters for Victoria T. Street, the appointed incumbent, and challenger Gilbert A. Diggs, a retired assistant school superintendent.

The third candidate in that race, Philip Pannell, president of the D.C. Young Democrats, has less money and fewer posters than either of his opponents, but yesterday he fielded a crew of volunteers to pass out leaflets, sometimes side by side with those for his rivals.

All three ward four candidates - Diggs, Pannell and Street - were interviewed yesterday morning on WHUR-FM and spent much of the day passing out leaflets and introducing themselves to voters.

By contrast, Barbara Lett Simmons, the only at-large member seeking re-election, spent the day in the Virgin Islands, where she is attending a three-day meeting of the National School Board Association.

Two of her rivals represent small parties - Afrodita Constantinidis, of the Socialist Workers Party, and Stuart Rosenblatt of the U.S. Labor Party. Both have used campaign forums to promote their party programs as well as to discuss school issues.

The fourth at-large candidate, Frank Shaffer-Corona, is former salesman who worked recently as a legislative analyst at the National Center for Community Action, and antipoverty group. He has been active in local Hispanic groups, but in the campaign has stressed his support for Supt. Vincent Reed's competency based curriculum, which Simmons has questioned.

Both Simmons and Shaffer-Corona carry the endorsement of the Washington Teachers Union.

The issue in most of the ward races has been which candidate can be more effective on the school board, rather than sharp differences in policy. Nearly all the candidates strongly support Supt. head, but there are significant differences in emphasis and style.

In ward eight, a seat being vacated by Julius Hobson Jr., candidate Genevieve B. Artis stresses the long time she has lived in Anacostia - 25 years - her membership on the region one area school board, and her experience as a social service aide in the Anacostia Pre-School.

One of her rivals, Wilbert Williams, is a lawyer who works for the U.S. Department of Agriculture as an equal opportunity specialist. He stresses his position as an advisory neighborhood commissioner, his post as a deacon in the Matthews Memorial Baptist Church, and his work as legislative chairman of the citywide D.C. Congress of PTAs.

The third ward eight candidate, R. Calvin Lockridge, is the fieriest speaker of the group and the most experienced politician. Until he moved here in 1973, Lockridge was a prominent black activist in Chicago, where he twice ran unsuccessfully for the alderman. He now is a member of the D.C. Democratic State Committee.

A former teacher and salesman, Lockridge served 10 months in 1973 as director of the Anacostia school decentralization project until he was ousted by its board. Since then he has held a series of jobs as an education consultant, most recently in Atlanta.

In the past elections, ward eight has had by far the smallest turnout of any part of the city. Fewer than 1,200 people voted in 1973, the last time it picked a school board representative - about 5 per cent of those registered. The citywide turnout in the last three school board elections has ranged from 10 to 12 per cent.

In other contests Tuesday:

Ward two has a spirited contest between Alverta Munlyn, an education specialist with the Center City Community Corporation, an anti-overty group, and Alaire Rieffel, a lawyer and Smith College graduate who heads the Ross Elementary PTA.

Ward three incumbent Carol Schwartz, a former teacher and vice president of the school board, faces two challengers, Kenneth T. Lange, a lawyer, and Gwendoline G. Reiss, a real estate agent.

Ward seven also has a three-way contest between Minnie S. Woodson, a retired teacher appointed to the board last January: Gloria Anderson, a program coordinator for Anacostians Concerned for Senior Citizens; and Rufus (Catfish) Mayfield, who hosts a radio program on WOOK.