A few more links I've come across while googling:

www.uspto.gov

http://www.c-sharpcorner.com/Security/ProtectILCode.asp

- Anti Cracking FAQ How to make cracking your programs a little
harder
( http://www.inner-smile.com/nocrack.phtml )

- Defending Shareware Against Cracks by Adam Smith
( http://www.senseofsecurity.com/sharenc.asp )

- Protect your programs from piracy
( http://webdon.com/vitas/antihack.asp )

- How To Protect Better
( http://www.searchlores.org/protec/protec.htm )