There is no direct way of writing to the system clipboard unless you use an external library as can be be found at Paul's site (Windows only).
http://www.ps-bridge-scripts.talktalk.net/
There are work-a-rounds see http://www.ps-scripts.com/bb/viewtopic.php?p=15322
The easy way is to write the information to a text file, here is an example of writing the filenames to a text file on the desktop.
The filename will be the same as the current folder name in bridge.
#target bridge
if (BridgeTalk.appName == "bridge"){
var FtoFiles = MenuElement.create( "command", "Filenames to file", "at the end of Tools");
}
FtoFiles.onSelect = function (){
var files = app.document.selections;
var fileNames = new Array();
for(var a in files){fileNames.push(decodeURI(files.spec.name));}
var folderName = decodeURI(Folder(app.document.presentationPath).name);
var f = new File(Folder.desktop + '/' + folderName + '.txt');
f.open('w');
f.write(fileNames.join('\n'));
f.close();
};