Yes but how many were enslaved?
None
Interesting article on that subject - "Did blacks fight in combat for the Confederacy?" at http://civilwargazette.wordpress.com/2008/03/13/did-blacks-fight-in-combat-for-the-confederacy/:
"One of the more interesting questions related to blacks serving in the American Civil War is this, did blacks (free or slave) serve in combat roles in the Confederate Army? Unquestionably the historical evidence is strong that some blacks – perhaps several thousand – did serve in the Confederate Army in unofficial, non-combat roles as servants, laborers, teamster, musician, cooks, etc. But the official record is very unsupportive that thousands of blacks served as official soldiers in the ranks of the Southern soldiers’ rosters.
"When we use the word official we mean that a black soldier would have been documented through the same paperwork process as a white man would have in terms of enlisting, mustering in or out, and perhaps applying for pension benefits after the war. It is this logistical paperwork process that leaves a trail for historians to study and interpret.
"But how strong is the primary historical evidence – letters, diaries, first-hand accounts, military records, etc., – that blacks served in combat roles for the South? It is an important question.
"Besides the fact that it is important to preserve accurate history it is also important to “get it right” when it comes to knowing who fought in the Civil War so that these individuals can be properly honored and their place in history duly noted. Some who favor a Southern perspective on the war, particularly defending the proposition that the South did not fight to preserve or defend slavery, have argued that thousands of slaves fought on behalf of the South thereby proving that they were generally supportive of the Southern way of life."
More at The Civil War Gazette website at above link.
For further reading on the role of Blacks serving in the Confederacy check out:
"Black Southerners in Gray, Essays on Afro-Americans in the Confederate Armies," edited by Richard Rollins
"The Journal of Confederate History Series, Vol. XI," published in 1994 by Southern Heritage Press, Murfreesboro, Tenn.
“Blacks in Gray”, by Jason H. Silverman. North & South Magazine, Vol 5, Number 3, April 2002: 35-45.
“Black Confederates”, by Bruce Levine. North & South Magazine, Vol 10, Number 2, July 2007: 40-47.
“United States Color Troops”, by Gregory J.W. Urwin in Encyclopedia of the American Civil War, edited by Heidler and Heidler: 2002-2003.
“African-American Soldiers, C.S.A.”, by Frank E. Deserino in Encyclopedia of the American Civil War, edited by Heidler and Heidler: 16-18.
“African Americans in the Confederacy”, by Edgar A. Toppin in Encyclopedia of the Confederacy, Volume One.