There is a patch in the downloads section, called "TBAmud 3.66 changes for windows" (here :
drive.google.com/open?id=0B40XbRH2Qbx5MFQ4SzNBSkViS0k
) .
This patch adds a new conf.h.win file - which will need to be copied to src/conf.h and which has a bug. It lacks the necessary import for winsock in the MSVC part, which is what the previous answer tells about.
It also includes the necessary MS VS project files to get started.
Unfortunately something is still not right after one does this - the mud has a bug with these settings causing it to crash after a couple of minutes. I have still not been able to pin it down - apparently somewhere we're either clobbering memory or freeing something we're not supposed to. This doesn't happen on linux or when compiled in cygwin, so it might be some library included by visual studio that's causing it.
So, I recommend that instead of going through all that trouble, you run tbamud under cygwin.