When Actor's Equity joins forces with the League of NewYork Theaters, the alliance of theatrical producters, you can be sure it's a serious matter. Should you be going to the New york theater next week, you, too, are welcome to join.

July 11 through 16 Equity members will be circulating petitions an hour before curtain time at all theaters demanding "the right of the people to a clean, safe Times Square area." The aim is to impress on property owners and city officials the need to upgrade the tawdry theater district.

Equity's executive secretary Donald Grody and the producers have corralled Alex Parkes, president of One Times Square, the old Times Tower building, to resume the electric ribbon of news around the building "if the area is upgraded as planned."

That "Porgy and Bess" tradition inaugurated by the Robert Breen-Blevins Davis production which orginally starred Leontyne Price and William Warfield, will be followed when the Gershwin musical plays its three-week run starting Wednesday at the Kennedy Center Opera House. This involves casting in depth.Bess will be sung by either Wilhelmenia Fernandez, Naomi Moody or Gail Nelson. Porgy will be played by Donnie Ray Albert, Robert Mosley, Bruce A. Hubbard or Michael Smartt, with Delores Ivory-Davis and Wilma Shakesnider alternating as Serena. Crown, Maria, Jake and Sportin' Life also will have alternating performers in this production of the Houston Grand Opera.

With two Alan Ayckbourn comedies scheduled next week, "Absent Friends" at the Eisenhower and "Absurd Person Singular" at Olney, a third joins the Virginia Players' summer repertory in Charlottesville, where "Hoe the other Half Loves" will join the current "I Do, I Do" for Wednesday-Sunday performances.

Cole Porter's songs form New York's "Unsung Cole" and London's "Oh, Mr Porter" this summer, but the Barksdale Theater. Hanover, Va., has a novel angle in "Red, Hot and Cole." This variation has a book by Randy Strawderman, James Bianchi and Muriel McAuley, imagining an Elsa Maxwell party during which notables of the period sing Porter songs often associated with their careers. This has been worked out with New York's Cole Parter musical and Literary Trust, and unlike revues which uncover forgotten Porter songs, this one includes the famous ones as well. Hanover, Va, just north of Richmond, is about 90 minutes out Route 95 and 301.

Two other musicals are in for summer runs. The Hallam Players of Prince George's Community College and the Maryland National Capital Parks will be going "Good News" on a tour startink Wednesday at Clinton. "Corousel" will be presented by Bethesda's Wildwood Summer Theater July 21 through Aug. 6 at Bradley Hills Presbyterian Church.

"Romeo and Juliet" has begun its pre-Sylvan Theater tour as the '77 Shakespeare Summer Festival produced by Ellie Chamberlain. In director Roger Meersman's cast are Lanny Thomas and Helena Light in the title roles, with Shepard Sobel as Mercutio, Leah Kremer as the nurse and John Elko as the friar. Glen Echo sees the play tonight and Friday; Rock Creek park (Military and GLover Roads) Saturday and Wednesday, Antietam Park at Sharpsburg , Md., July 14 and 15; and Harpers Ferry July 16 and 17. The Sylvan Theater on the Marymount grounds sees the play July 20 for three weeks. Performances at 8&30 p.m.

Living Stage. Arena's Outreach Company, will begin its 12 annual series of summer workshops for children, teens and adults on Monday at Arena Stage. Morning sessions will be for children from 6 to 12, afternoons will be for teen-agers and evenings for adults. Further information at 554-