This is a JavaScript function I wrote for an upcoming statistics tracking website of mine that allows you to get the Google Gears version of a visitors browser. I decided to pull it from my site due to the Google Gears version not really being of interest to anyone - but someone may well find it useful.

function gearsversion(){
     if (window.google && google.gears){
     var gearsinfo = google.gears.factory.getBuildInfo();
     var gearsversion = gearsinfo.split(';');
     return gearsversion[0];
     }
}

I did it a dumb ass way. See the factory API docs to get the version properly. (Thanks Chris)