Here is a list of useful links
Videos and tutorials
Security tube: www.securitytube.net
Corelan: www.corelan.be
Blogs I have found helpful
Lupin: grey-corner.blogspot.com
http://g0tmi1k.blogspot.com/2011/08/basic-linux-privilege-escalation.html
Other info
Alpha-numeric assembler opcodes for making custom shellcode:
http://skypher.com/wiki/index.php/Hacking/Shellcode/Alphanumeric/x86_printable_opcodes
Products and services
Browser security checker: browsercheck.qualys.com
URL decoder: http://meyerweb.com/eric/tools/dencoder/
Base64 decoder: http://www.opinionatedgeek.com/dotnet/tools/
Chrome plugins http://blog.anantshri.info/chrome-extensions-for-security-professionals/