Most of the articles, unfortunately, are dated. But I will link them as I find them ...
UPDATE: Forgot to add this article in original post: The Prisoners of War, By Ian Urbina, AlterNet, October 27, 2003. Article on Unicor/FPI and the broader prisoner labor issue. Reads like an NPR piece - somewhat factual but just can't help taking jabs at republicans. Let's be honest here - this is a non-political site - but the legislation that effectively repealed the 1935 Act and thereby brought back prison labor was the Justice System Improvement Act of 1979 (Public Law 96-157). The Act was sponsored by Ted Kennedy, the House was controlled 276 to 157 by the democrats, the Senate 58-41-1 by the democrats, and Jimmy Carter was POTUS. What did W or the pubs have to do with that? Do you find it equally irritating when people can't keep politics to themselves?
'Made in USA' ... but By Convicts, Christian Science Monitor. January 14, 1998. Discusses Broward Optical, run out of Broward (FL) Correctional Institute, and the general prison labor situation.
Prison Labor: Workin' For The Man, by Reese Erlich, originally published in Covert Action Quarterly #54 - Fall 1995. One of the better articles, includes footnotes and informative (if dated) use of data.
Prison Labor: Profits, Slavery and the State, by "MC12," Maoist Internationalist Movement. Undated. The article has a decided bias against the process of using prisoners are laborers, and loosely uses the term "forced labor" as if the system in the United States were akin to the USSR's gulags or Communist China's laogai.
Doing time, 9 to 5, by Steven Elbow, Copyright 1995 Isthmus, Madison, WI. Plenty of examples, focused on local Wisconsin issues. Reads like a well-research op-ed piece.
Prison labor on the rise in US, by Alan Whyte and Jamie Baker, May 8, 2000. Published by the World Socialist Web Site, the article focuses on the relationship of prison labor, traditional labor unions, and legislation.
Prison Labor: Some Facts and Issues, by Karen Miller, copyright 2000. A lot of data, but presented in a narrative, and also inaccurate in two instances that caught my eye in a quick review. She cites the Hawes-Cooper Act as occurring in 1935 (it was 1929), and the Ashurst-Sumners Act as occurring in 1940 (it was 1935).