In the presentation on "Challenging the Role of the Architect" I talked about the need for a team Wiki where the lower-level details of the system documentation should be published. Some people have asked for more information about this - what wiki do I recommend. This is a very intersting question because it is a little like asking 'what source code repository should I use?' in that the answer is quite clearly 'it depends'. Let me take a stab at a piece of logic though and we'll see if that helps:
If you are working with resonably recent version of .NET then the answer is actually pretty simple. In this case you will, of course, be using Visual Studio Team System for development and will be using the features and facilities to manage your project in Team Foundation Server. I'm hoping that you are anyway, because as I have said a few times there is no better tool for managing software projects than Team Foundation Server to the point where I recommend that even teams that are building using Java (or a derivative) use Team Foundation Server through a plug-in into Eclipse. But I digress and I can talk more about that another day.
Anyway, assuming that you are using TFS you'll note that TFS integrates nicely into SharePoint 2007 to provide a project portal. Given that this is the case the best option then in to include the Wiki as a part of that portal. Personally, I find the built-in Wiki functionality in SharePoint to be sufficient for this kind of documentation and it provides the easiest, and best integrated, solution. You could consider using a thrird party Wiki tool like Confluence from Atlassian to edit the Wiki and then surface it through SharePoint using the available plug-in from Atlassian .
If (heaven forbid) you aren't using TFS then you could just use Confluence. There are, of course, many open source options available but I must confess that I don't know them all that well. Check out what is available through CodePlex or your favourite reputable open source repository/community and review what other people have said before making a selection. I'd recommend that you consider the ability to export content to be an important part of the decision in case you outgrow your solution and need to move to another.
I've recieved a few questions from people along the lines of "I'm a Developer and I'm about to work as an Architect" or "I just got put in an Architect role and I'd like to know what I need to know to be a good Architect". This is obviously a big and complex question, and so I am writing a big and complex set of answers. Trouble is that this is taking me ages though and I know that everyone is waiting for something to start on, so I have pulled out a few things that I suggest that you start with and I'll add more detail along the way.
Firstly, there are a couple of books that I think capture the essence of Architecture as a part of the engineering disipline of software development:
- Code Complete: A Practical Handbook of Software Construction by Steve McConnell
- Professional Software Development by Steve McConnell
- Design Patterns: Elements of Reusable Object-Oriented Software by Erich Gamma
- The Mythical Man-Month: Essays on Software Engineering by Frederick P. Brooks
Surprisingly I don't have a lot of other books on Architecture that I really, really, like. There are other books in related displines that I would recommend that any Architect should read and understand though, and if you have seen my talks in the area you'll know that I have a firm belief that Architecture is about much more than putting code or components together. So, I would also recommend the following as required reading:
- The 7 Habits of Highly Effective People by Stephen R. Covey
- 10 Natural Laws of Successful Time and Life Management by Hyrum W. Smith
- The Power of Positive Confrontation: The Skills You Need to Know to Handle Conflicts at Work, at Home and in Life by Barbara Pachter
That will do for now. I'll post more information soon on this subject but the above pile of books should keep you busy for a while. 
Here's an interesting article by Peter Koen that refers extensively to the Virtualisation Maturity Model that Peter Richardson and I invented for Edition 18 of The Architecture Journal. Lots of fun to see that we are being quoted, even if I wasn't aware that the article existed until today: http://architects.dzone.com/articles/part-1-move-blue-cloud-save. It is quite a good read though, so I recommend you go and have a look.