<p>I am re-building our poorly designed web application from scratch, and wanted to get into TDD and basically "do things right" as kind of a learning project.  What tools, processes, and resources are recommended to do it "right" from the start?  I will be working alone as the architect and developer, with the backup of a business analyst and business owners for usability testing and use cases.</p>

<p>EDIT:
Right now we use SourceSafe for source control, is there any reason technologically that I'd want to try to get us to switch to subversion?</p>

<p>EDIT #2:
Looks like the consensus is:
Cruise Control.NET
Subversion(if I want to stop using SourceSafe)
ASP.NET MVC
NUnit for unit testing
Resharper</p>

I highly recommend that you take a look at
MVC for ASP.NET
if you want to make unit testing a high priority in your development process.  It sounds like it is perfect for what you are trying to do.
I would also recommend
CruiseControl.NET
for continuous integration (this is important if your team is going to grow).
Subversion is my favorite source control system when I am working on small teams.  Use
Tortoise SVN
for Windows Explorer integration.