The internet is full of high-quality, free documents on every topic conceivable, including Comp Sci. Has it been reviewed, professionally edited and typeset? If you really think there are people who would pay for your documents, then approach an e-book publisher, or create your own e-book, and try to sell. IMHO - If you're good at Comp Sci then you're going to make a lot more money, a lot more quickly, by actually doing Comp Sci instead of selling technical documents. You can even do all kinds of Comp Sci projects on the internet with oDesk, etc. and get paid well.