Some time back I posted notice of an excellent Fred Halliday journal article (about 40 pgs. or so) from 1998 on the PDPA, (which expanded greatly on his two classic New Left Review pieces from the immediate aftermath of the Soviet invasion) and it's violent internal factionalism and the Soviet occupation of the 80's. For newbies here, I can send offlist again to the curious. (BTW, found it via the great resource alot of libraries have, EBSCO.)
Other resources, "The Tragedy of Afgahnistan, " by a Pakistani leftist (blanking on his name, my copy is at home), published by Verso, get the revised 2nd ed., preface by Halliday. Great on the ground analysis and background on Afghan communism.
Doris Lessing (yes, the ex-Communist novelist), "The Wind Blows Away Our Words, " Random House/Vintage Books, mid 80's. G. Chaliand, author of the classic, Revolution In the Third World, "Penguin Books, preface by Wallerstein, has a book on Afghan mujahdeen. See his anthology from U.C. Press on Guerilla struggles for his classic NYRB piece from the early 80's. (Old time anti-Vietnam War activists may recall his, "The Peasants Of North Vietnam, " late 60's published by Penguin Books.
http://www.www.csf.colorado.edu/mail/psn/2001/msg01918.html
Chapter by Ahmed Rashid in a book published by neo-con org. Freedom House in the early 80's.
M. Hasan Kakar, "Afghanistan: The Soviet Invasion and the Afghan Response, " U.C. Press. By a liberal Muslim imprisoned by the PDPA.
"The Hidden War: A Russian Journalist's Account of the Soviet War, " Grove Press, have not read, blurbs look good. Michael Pugliese