I have published my gomoku (5 in a row) game as a free-to-take project on sourceforge. I was not touching the source since 2004 now, and i dont plan to develop further myself. If anyone finds it interesting, or just wants snippets from the code, feel free to use it, it is licensed under GPL.
The latest executable is still available from my homepage, or from sourceforge itself. Sourcecode is available in SVN repo.