As long as a "shameless self-promotion" is useful for others we don't frown upon it
I posted quite a lot of my scripts here on the forum and nobody complained about it yet.....
Why don't you write a little guide or howto for your script for our Howto/Guides section?
Attach the script and for download and mention the google code url as reference for the latest version.
That way people still can use, study or hack on your code when google goes bankrupt or when the FBI seizes the code.google.com domain for whatever creative reason they may come up with