Are Secure Internet Transactions Really Secure?
This paper describes how many small business claim to be offering a secure order form, when in fact, they really are not. The paper shows how the insecurity occurs, and offers a few solutions to the problem.
http://www.jsweb.net/paper.htm

Cgisecurity.com
This site is designed to help user to learn about what kinds of security risks exist and how to prevent them from happening.
http://www.cgisecurity.com/

Client Side Trojan
By clicking on maliciously formed HTML tags users can unknowingly perform undesirable actions.
http://www.zope.org/Members/jim/ZopeSecurity/ClientSideTrojan

CIAC: Unix NCSA httpd Vulnerability
An advisory detailing a vulnerability that has been discovered in the NCSA WWW server software (httpd).
http://www.ciac.org/ciac/bulletins/f-11.shtml

Download Accessdiver
Detect security failures on any kind of web sites.
http://www.accessdiver.com

Web Security: A Matter of Trust
Collection of original articles.
http://www.w3j.com/7/

W3C Security Resources
Provides an overview of web security and links to security initiatives such as PICS Signed Labels, and XML-DSig.
http://www.w3.org/Security/

World Wide Web (in)Security
Demonstrations of security risks and advice for safe use of a web browser.
http://www.swcp.com/~mccurley/danger/danger.html

W3Schools.com: Web Security
Covers basic privacy issues.
http://www.w3schools.com/site/site_security.asp

Total Simplicity
Total Simplicity is a full on technical company providing hosting, custom programming, security, and online stores.
http://www.totalsimplicity.com

The Open Web Application Security Project
How to build, design and test the security of web applications and web services.
http://www.owasp.org

Web Spoofing
Full text of a paper discussing an 'attack' that threatens both privacy and data integrity. Written by Edward W. Felten, Dirk Balfanz, Drew Dean, and Dan S. Wallach. Available in various formats including PDF and Postscript.
http://www.cs.princeton.edu/sip/WebSpoofing/

COAST Hotlist: Security in the WWW
A collection of links related to WWW security.
http://www.cerias.purdue.edu/tools_and_resources/hotlist/

Northfell
Article on website hacking covering footprinting, IP scanning and an example IIS hack. Also has computer security weblog and an overview of BS7799.
http://www.northfell.com/

Hacking Exposed: Web Applications
Book that covers how to hack web applications, and how to secure against the attacks detailed. Author profiles, links to tools referenced in the book and reviews.
http://www.webhackingexposed.com/