Configuration Management Tools

Source Control

Tortoise
TortoiseSVN is an easy to use SCM / source control software for Microsoft Windows and maybe the best standalone Subversion client there is. It is implemented as a Windows shell extension, which makes it integrate seamlessly into the Windows explorer.
http://tortoisesvn.net/

Ankhsvn
AnkhSVN is a Subversion SourceControl Provider for Visual Studio. The software allows you to perform the most common version control operations directly from inside the Microsoft Visual Studio IDE. With AnkhSVN you no longer need to leave your IDE to perform tasks like viewing the status of your source code, updating your Subversion working copy and committing changes. You can even browse your repository and you can plug-in your favorite diff tool.
http://ankhsvn.open.collab.net/

Build

Nant
NAnt is a free .NET build tool. In theory it is kind of like make without make's wrinkles. In practice it's a lot like Ant.
http://nant.sourceforge.net/