Interesting Links

PCI
A forum site for PCI professionals, which is at times more informative than the PCI Council’s website: http://forum.paymentsecuritypros.com/
This guy is a very active & knowledgeable member of the PCI forum who writes well: http://pciguru.wordpress.com/
PCI FAQ of PCI Council: https://www.pcisecuritystandards.org/

ISO 27001
Here you find a free toolkit with a lot of helpful contributions around the ISO standards: http://www.iso27001security.com/html/iso27k_toolkit.html
Buy and download the standards http://www.iso.org/iso/home.html

Security Assessment & Best Practice
Very comprehensive and free audit questionnaires, shared assessments for service providers: http://www.sharedassessments.org/value/
Centre for Internet Security (CIS) audit & benchmark tools http://cisecurity.org/en-us/?route=default
Best practice & detailed guidelines on just about anything related to security http://csrc.nist.gov/index.html
Security Awareness & Training http://www.popcorntraining.com

General/Cool Sites  
Security Research http://securosis.com/
Security Architecture http://www.opensecurityarchitecture.org/cms/
Information Security Africa http://www.isgafrica.org/blog/
Security Architecture http://www.opensecurityarchitecture.org/cms/