Four folk and country icons team up for what promises to be a very informal collaborative concert at the Pabst Theater tonight at 8 p.m. Three of the four -- folkie
Patty Griffin, country traditionalist
Buddy Miller and country legend/alt-country queen
Emmylou Harris -- launched a similar tour in 2004 called the "Sweet Harmony Traveling Revue," but this one, "Three Girls and their Buddy," swaps Gillian Welch and David Rawlings for
Shawn Colvin, the folk-rocker who scored a major hit in the late '90s with her revenge tale, "Sunny Came Home."