May 3, 1981

More than 2,000 new housing units are scheduled to come on the market in Queens in the near future and sales of 500 more units are under way. Some single-family homes are included, but the bulk of development is in high-rise condominium apartments and in two- and three-family houses in which the buyer also gets rental units. Many of the new housing units are in projects that have been tied up for several years by community opposition and litigation. No rental apartment buildings are under construction. ''Queens is the best market for the immediate future,'' said Larry Hahn, who has built more than 4,000 homes on Long Island over the last 26 years under the name House Beautiful. He does not anticipate growth on Long Island over the next five years and he sees Queens as a stable, attractive borough for middle-class housing with easy access to Manhattan. He is building 109 town houses in Bayside.

AS they sought to assess the impact of the proposed Reagan budget cuts on government programs in Westchester, county officials warned last week that they contained sharp reductions in Federal funds in the field of transportation and highways. Many millions of dollars in Federal assistance now flow each year from Washington to help run or equip bus and rail systems or to pave roads in the county. If the proposals are adopted by Congress, the officials said, several millions of that aid would be eliminated. The money would have to be replaced locally or services cut back. It is the latter option that Westchester officials seem particularly loathe to consider, especially when its buses and commuter rail lines have been in the midst of a resurgence in recent years, reversing long-term declines.

The United States is becoming increasingly Republican, but it is becoming more conservative only selected issues, according to the latest New York Times/CBS News Poll. Democrats still outnumber Republicans, but the Democratic lead is only half what it was when last year's Presidential campaign began. The changes, as measured by the poll, offer Republicans an opportunity to effect a classic political realignment comparable to the Democratic accession to power in the 1930's. Charles T. Manatt, chairman of the Democratic National Committee, said his party's losses among younger Americans and Southerners had only identified groups the party must work on. Richard Richards, the Republican National Chairman, said he thought the shifts did not yet mean realignment, but that ''people are giving the Republican Party a chance.''

The Senate Ethics Committee will meet tomorrow or Tuesday to begin considering action against Senator Harrison A. Williams Jr. of New Jersey because of his conviction Friday night on bribery and conspiracy charges. The panel, headed by Senator Malcolm Wallop, Republican of Wyoming, will meet privately in Washington to discuss ''steps necessary and appropriate to the discharge of its constitutional responsibility to determine the fitness of this member of the Senate to continue to hold an office of public trust,'' a committee spokesman said yesterday. The announcement came amid expressions of regret by the New Jersey Democrat's Senate colleagues, mingled with concern for the image of Senators and other public officials. 'A Great Personal Tragedy' There was also criticism of the tactics used by the Federal Bureau of Investigation in its Abscam operation to uncover political corruption. Senator Bill Bradley, the junior Senator from New Jersey, said the conviction was ''a great personal tragedy for Senator Williams and his family.''

AGE By JOHN VINOCUR AUTHEUIL, France Over the past few years, Simone Signoret has played an aged prostitute, a revolutionary, a failed actress, an East European spy, a Gaullist underground fighter, an alcoholic with a limp, a peasant from the Dijon countryside, a housekeeper, an aristocrat called Lady Vamos, and on and on. She has forgotten for the most part about Alice Aisgill, the role in ''Room at the Top'' that won her an Oscar and launched, like little ships, a generation's fleet of private dreams. A couple of decades ago, Miss Signoret represented the kind of mature seductiveness that many young men, but particularly Americans not quite at ease with the Gina Lollobrigidas and Jayne Mansfields and the sex-by-the-centimeter standards of the times, wished for themselves. As Alice, the French mistress, she was not really beautiful, but better - at the edge of beauty - and she seemed what was called, a bit euphemistically, knowing, mature and wise. For a while back there, she could have lunged at a kind of stardom that probably would have made it difficult or impossible for her to portray, much later, either a cleaning lady or a ruined old whore, or, as in her latest film, ''I Sent a Letter to My Love,'' which opens in New York today at the Paris Theater, an old-maid sister - frustrated, passionate, pathetically and touchingly conniving.