I support the Agile Modeling and Agile Data work being led by Scott Ambler. These two sites are among the best other resources for agile developers interested in modelling, architecture and architecture issues.

The Agile Alliance is an organisation dedicated to promoting agile development methods. Not everything they say is right for the Agile Architect, but it's still a good source of ideas and other links.

The following are good reference sources on topics related to software architecture: 

• CBDi Forum - A key source on Component-Based Development, service-based architectures, and a lot of related topics including EAI. They have some pretty good free content, and a regular email newsletter. A subscription is recommended if these are areas of interest to you. 
• EBizQ Network - A cross-industry review group looking at issues related to EAI and message-based integration in particular. They have some good free content, and a regular newsletter.
• IBM's Patterns for eBusiness - A useful catalogue of analysis, business and architectural patterns for eCommerce systems.
• Reliability Software Listing - A useful listing of software and reference sources on the topic of reliability assessment, for both hardware and software.
• Microsoft's Visual Basic Homepage - The fount of all knowledge (well, some of it!) for VB.
• British Computer Society Testing SIG - A very good starting point for information on software testing.
• Bredemeyer Consulting Resources for Software Architects - This is a first-class site for anyone interested in the process of software architecture and the role of the architect, with a substantial amount of free content.
• Nucleus Research - An unusual organisation, Nucleus Research concentrate almost entirely on evaluating Return On Investment (ROI) for various software and technology initiatives. It's an excellent place to start if you're trying to sell the value of technology.
• The Cynefin web site has a number of useful articles on the use of stories, and the Cynefin Framework which describes different decision-making and problem-solving environments.
• VRAPS.COM David Kane, David Dikel, and Jim Wilson wrote an excellent book entitled "Software Architecture: Organisational Principles and Patterns" It's about how to make architectural changes across an organisation. It's very much about the softer aspects of selling ideas, getting buy-in, and then seeing changes through. This site presents a lot of useful material from and related to the book and their model for architecture. You can also read my review of their book.

I take an active interest in issues around user interface design, and how people interact with computer systems. To my mind, one of the most important initiatives in recent years is the Expressive Systems movement lead by CSC's Richard Pawson. You can read my review of his book, or visit the Expressive Systems web site:

Larry Constantine and Lucy Lockwood's site, ForUse, is a very good source for lots of information on software usability and how this can be defined through modern system development approaches such as UML. In particular they have several papers which describe agile approaches to controlled user interface design.

There's also a growing movement which is trying to apply patterns to user interface design. I've been disappointed in the books so far, but the following two sites have useful pattern catalogues:

• Jennifer Tidwell's User Interface Patterns
• The Interaction Design Patterns Home Page