Bill Mack, one of the most prominent and influential DJs in country music history, will begin hosting a show on XM Satellite Radio this summer. Mack turned off his microphone Thursday (March 29) at Fort Worth, Texas, radio station WBAP, where he became nationally famous for his overnight show. Mack, who began in radio in 1951 and worked as an announcer for Bob Wills and Buck Owens, joined WBAP in 1969 and had been there since -- save for a six-year spell in the 1980s when the station fired and rehired him. Mack wrote "Blue" in 1958 for Patsy Cline, but it wasn't a hit until LeAnn Rimes launched her career with the song in 1996.