Two events scheduled in Washington today seek to call public attention to the importance of American libraries.At noon, the American Library Association plans to hold a "Rally for America's Libraries" at the Martin Luther King Memorial Library. The program includes testimonials by library users. "We are speaking out to remind the public that they deserve to have accessible and affordable information," says Patricia Glass Schuman, president-elect of the American Library Association. The celebration marks the conclusion of a five-city whistle-stop tour, "Rally on Wheels," that began July 4. The Washington rally comes on the heels of the American Library Association's 110th annual conference in Atlanta last week. There, the organization launched a year-long campaign called "Libraries are worth it," encouraging communities to organize local activities in support of libraries. Today also marks the opening of the second White House Conference on Library and Information Services. During the conference, which ends July 13, 900 delegates from across the country will discuss ways to improve library and information services - a first step, organizers say, toward increasing literacy and the nation's productivity. The first White House conference on libraries was held in 1979. It produced 64 resolutions that were sent to the President, Congress, and various government agencies. Fifty-five resolutions have been acted upon. As further evidence of the broad-based literary constituency represented in Washington this week, Friends of Libraries U.S.A., a Philadelphia-based group, has gathered more than half a million signatures in support of libraries. Leaders of the organization plan to present the signatures to the White House.