What? There's nothing intrinsically illegal about a solution manual. If I own a textbook and do all the problems and write down how to do them, I have not committed a crime. The crime is distributing (and especially selling) copyrighted material without permission.
you guys know what "solution manual" is. materials that students shouldn't have access but are transfered person to person.
you solved all the problems, good for you, but you are not supposed to make a pdf and post it online.
I'm not sure where you got this idea, but the term solutions manual most commonly refers to a booklet typically written and published by the same authors and publishing company that wrote the original textbook and is frequently sold alongside the textbook.
Some examples include:
Halliday Resnick & Walker: http://www.amazon.com/gp/product/047055 ... VYTZ8F3XQR
Molecular Quantum Mechanics: http://www.amazon.com/Solutions-Manual- ... 0198559682
Quantum Chemistry: http://www.amazon.com/Student-Solutions ... pd_sim_b_4
and all of the books that the OP referenced, so far as I could tell, were these type of professional/published solutions manuals which in all likelihood were obtained illegally and were being distributed illegally.
and just to be clear, the OP never asked to be payed for giving away solutions manuals. He/she was just offering to give them away, which is still entirely illegal.