The latests versions of Node (v0.3.6 and better) can be built with mingw. This is work in progress; expect this node build to be unstable and very much incomplete.
This will assume you're checking out and compiling node in c:\node
git clone https://github.com/ry/node.git
These are known issues with the build process. A list of known issues with mingw-built node can be found found in TODO.win32.
Some people have reported problems getting this to work. If you are affected by this, use git from the windows command prompt.
Having Microsoft Visual Studio installed confuses the V8 build system. This is a know issue, there is currently no good solution for it.
Linking with openssl is currently unsupported. Use