This shellcoder handbook is good...
http://www.amazon.com/Shellcoders-Handbook-Discovering-Explo...
And articles such as this one by steve hanna
http://www.vividmachines.com/shellcode/shellcode.html
and this one by Aleph One on phrack,
http://phrack.org/issues/49/14.html
(by the way, many articles on phrack are really good)
Some more recent versions of smashing the stack are,
http://www.mgraziano.info/docs/stsi2010.pdf
https://paulmakowski.wordpress.com/2011/01/25/smashing-the-s...
also check out the ezines by 29A -- although they are old, but you know, some good stuff are still really good today...
just do a little search...there are tons of articles out there on this topic...