If you are looking for a single place to get most of Information Technology Security related whitepapers, documentation and opinions, try looking at www.securitydocs.com. It has reliable postings and a wide variety of topics that you can use to learn and if you are up for it, create documentation and post it for other's benefit.
Some of the topics include;
Security Basics
Application Security
Certifications
Enterprise Security
Exploits
Architecture
Firewall
Security Tools
Security Policies
One of the topics, which i am personally interested in is Vulnerability Assessment. There's a decent article on that site that one can benefit..here's a summary of the article.
The intention of this paper is to provide basic information to those who have recently entered the security field, provide some insight as to why a vulnerability assessment is necessary provide an overview of the vulnerability assessment process from discovery to baseline standardization, provide some assistance to those who want to perform a vulnerability assessment but do not know where to start.