In what may be the least unexpected bit of stunt casting in ABC's history, Regis Philbin will guest star on ''Hope & Faith'' during sweeps month in November. Kelly Ripa's new sitcom, which debuted to strong numbers last Friday, stars the ''Live With Regis and Kelly'' daytime cohost as a fallen soap star. In the upcoming episode, her morning pal will play Handsome Hal Halverson, a used car salesman who auditions the down-on-her-luck actress for a commercial. At least ABC didn't cast him as a game show host.

