You can checkout the project from http://wintectool.googlecode.com:
svn checkout http://wintectool.googlecode.com/svn/trunk/ wintectool
Note that this is a development version and, therefore, may or may not work for you.
You’ll find known good versions in the tags directory.
You can also download (using right-click and save as) the script without SVN at: http://wintectool.googlecode.com/svn/trunk/wintectool.
The script requires Perl with Device::SerialPort (would probably also work with Win32::SerialPort), GD, Date::Time, Time::Hires and File::Slurp.
On the One and Only Linux Distribution (and its friends) the following command should make you ready to go:
sudo aptitude install libdevice-serialport-perl libgd-gd2-perl libdatetime-perl libtime-hires-perl libfile-slurp-perl
The script has built-in documentation and help using POD. Say ./wintectool --man to read it.
It is Free Software under the Artistic License. See the documentation for details.