The New York City Labor Chorus. of which I am a member, sings Spanish civil war songs: it sings "Si Me Quieres Escribir"on its CD entitled "Hats off to Labor." We sang that at the memorial for Moe Fishman in November 2008. It sang Spanish Civil War songs with the Cor Corchion in Wales in 2009.

In NYC, John Pietaro of The Flames of Discontent has a version of "Viva La Quince Brigade" on his new CD: "The Revenge of the Atom Spies" -- I heard his group perform it at the Brecht Forum in New York City recently.
The San Francisco Bay Area Labor Heritage Chorus sings a Spanish Civil War Medley: it is on a CD called "The Great Choral Convergence" recorded 2004 in Washington DC.
Si Kahn is a North Carolina based folk musician who has written a song about Clarence Kailin, a Lincoln Brigade volunteer, that I heard him sing at the Tamiment Library in New York City
in 2009.