How can I log into an X server from Mac OS X? I know that ssh -X username@host will log me in and I will have the capability to run X applications.

On Cygwin/X you can log in and have a whole X session from your computer... and it will look something like this:

How can I replicate this?

Using this batch script:

@echo off
SET DISPLAY=127.0.0.1:0.0

SET REMOTE_HOST=%1

IF "%REMOTE_HOST%" == "" SET REMOTE_HOST=10.0.0.1

SET CYGWIN_ROOT=\cygwin
SET RUN=%CYGWIN_ROOT%\bin\run -p /usr/bin

SET PATH=.;%CYGWIN_ROOT%\bin;%PATH%

SET XAPPLRESDIR=
SET XCMSDB=
SET XKEYSYMDB=
SET XNLSPATH=

if not exist %CYGWIN_ROOT%\tmp\.X11-unix\X0 goto CLEANUP-FINISH
attrib -s %CYGWIN_ROOT%\tmp\.X11-unix\X0
del %CYGWIN_ROOT%\tmp\.X11-unix\X0

:CLEANUP-FINISH
if exist %CYGWIN_ROOT%\tmp\.X11-unix rmdir %CYGWIN_ROOT%\tmp\.X11-unix


if "%OS%" == "Windows_NT" goto OS_NT

echo startxdmcp.bat - Starting on Windows 95/98/Me

goto STARTUP

:OS_NT

REM Windows NT/2000/XP
echo startxdmcp.bat - Starting on Windows NT/2000/XP

:STARTUP

%RUN% XWin -query tekknolagi.dyndns.org -clipboard -lesspointer -scrollbars -screen 0 1050x1655@2 -screen 1 1680x985@1