It seems as though Louisville coach Rick Pitino is poised to take a(n unprecedented?) third different program to the Final Four...regardless, Louisville is third different program that Pitino has taken to a regional final...
Here is a (non-comprehensive) list of coaches taking three different programs to a regional final (or beyond)...
Gene Bartow: Memphis State (1973), UCLA (1976), UAB (1982)
Lon Kruger: Kansas State (1988), Florida (1994), Illinois (2001)
Rick Pitino: Providence (1987), Kentucky (1992-1993, 1995-1997), Louisville (2005)
Eddie Sutton: Arkansas (1978-1979), Kentucky (1986), Oklahoma State (1995, 2000, 2004)