Secure Programming for Linux and Unix HOWTO
http://www.dwheeler.com/secure-programs

Secure Programming Checklist:
ftp://ftp.auscert.org.au/pub/auscert/papers/secure_programming_checklist

Secure Unix Programming FAQ:
http://www.whitefang.com/sup/

Security Code Review Guidelines:
http://www.homeport.org/~adam/review.html

Robust Programming:
http://olympus.cs.ucdavis.edu/~bishop/classes/ecs153-1998-winter/robust.html

The Unix Secure Programming FAQ:
http://www.sunworld.com/sunworldonline/swol-08-1998/swol-08-security.html

How To Write a Setuid Program:
http://olympus.cs.ucdavis.edu/~bishop/scriv/Bish86.pdf

UNIX Security: Security in Programming:
http://olympus.cs.ucdavis.edu/~bishop/scriv/1996-sans-tut.pdf

"How to find security holes": (new link)
http://www.pobox.com/~kragen/security-holes.html?

FreeBSD Security
http://www.freebsd.org/security/security.html

"Unix Power - Security":
http://www.unixpower.org/security/

"Shifting the Odds: Writing (More) Secure Software, by Steve Bellovin."
http://www.research.att.com/~smb/talks/odds.ps