Xming is the leading free unlimited X Window server for Microsoft Windows (XP/2003/Vista). It is fully featured, light and fast, simple to install and because it is standalone native Microsoft Windows, easily transported portable as a Pocket PC X server. It is totally secure when used with SSH and optionally includes an enhanced PuTTY Link SSH client and a portable PuTTY replacement package.
Xming is cross-compiled on Linux for Microsoft Windows (32-bit x86), using MinGW, mainly from X.Org source code. It is kept current and secure with updates for X11, XKB, FreeType2, Pthreads-Win32 and Freedesktop Bugzilla.