Alan Cullison, a journalist, covered the events in Afghanistan for Wall Street Journal in late 2001. Cullison was offered to buy a bunch of computers from a local Al-Qaeda office on the day Kabul fell. Cullison bought an IBM desktop and a Compaq laptop for $1100 and copied the contents before submitting the same to CIA agents in Afghanistan. Cullison shares some of the electronic messages in Atlantic Monthly. It has interesting trivia about Al-Qaeda's financial operations and their involvement in the Taliban movement.
The article can be accessed at: http://www.theatlantic.com/doc/200409/cullison
An interesting reading. A login name/password for accessing the same is required. But the folks at \\.theatlantic.com are not very serious of security issues I guess, a bugmenot/bugmenot can get you in ;-)