SKIP SPENCE, 52, an original member of the rock group Jefferson Airplane and founder of the short-lived but influential band Moby Grape, Friday, in San Francisco. (Spence, who had long battled alcoholism, schizophrenia and periods of homelessness, died just weeks before the release of “More Oar,” a CD album tribute to him featuring such musicians as Beck, Robert Plant, Tom Waits and members of R.E.M.) . . . BILL WENDELL, 75, veteran radio and TV announcer perhaps best known for his “Late Night” introduction of “Da-a-avid Letterman!,” Wednesday, of complications from cancer, in Boca Raton, Fla.