Three high-profile members of the MuzikMafia — Gretchen Wilson, John Rich and Cowboy Troy — will perform a new song, “Our America,” with the Boston Pops on July 4. The collaboration will be included in the Boston Pops Fireworks Spectacular to be broadcast live on CBS. The song incorporates elements from “The Star-Spangled Banner,” the Preamble to the Constitution, Martin Luther King’s “I Have a Dream” speech, the Pledge of Allegiance and the Declaration of Independence. A studio version of the song will be available for a free download on www.ouramerica2005 for five days only, beginning Friday (July 1). Wilson and Big & Rich will also include it as a bonus track on their next albums.