Last month's performance of "Love Letters" by actress Betsy Palmer at Munster High School attracted both praise and applause. If you missed the show and you're a fan of the play, here's an idea for this Mother's Day weekend. Actor Robert Wagner, 75, and his wife Jill St. John, 65, will perform "Love Letters" for one dinner show at 6 p.m. Saturday at The Rialto Square Theatre in Joliet. Tickets range from $32.50 to $65.50 and are available by calling (815) 726-6600. Other famous celebrity couples who also have performed "Love Letters" in the past include Charlton and Lydia Heston, Jayne Meadows and Steve Allen, John Rubinstein and Kathleen Turner, and Robert Wagner and Stefanie Powers.