I've written some enhancements for stunnel running under
Win32, specifically NT/2000.  It includes support for
compiling under MS Visual C++ 6.0, native NT service
support (from the FAQ it sounds like a lot of people ask
about this), and NT event logging.  I think I've
got everything correctly  surrounded with ifdefs
because it still compiles and runs fine on my linux
and freebsd boxes, but I haven't done extensive testing.

There are detailed instructions on setting it up added
to the INSTALL.W32 file.  It's based off the 3.14 release
code.

I'm at work so hopefully my windoze mail client won't munge
up the attachment too badly ;)