Is there a way (script) to automate the process of adding a comp to a bunch of comps?

I think Dan's code needs some explicit UI, not just the automated alert() so AE doesn't return to the UI and forgets the script...

Mylenium 

That would be a pretty simple script. Here's an attempt at it. Select your source comp, run the script, select the destination comps, and click OK in the dialog.

function addCompToOtherComps(){
	var mySelected = app.project.selection;
	if (mySelected.length != 1 || ! (mySelected[0] instanceof CompItem)){
		alert ("Select single source comp in Project panel.");
		return;
	}else{
		var sourceComp = mySelected[0];
	}
	alert ("Select destination comps and click 'OK'");
	var destinationComps = [];
	mySelected = app.project.selection;
	for (var i = 0; i < mySelected.length; i++){
		if (mySelected[i] instanceof CompItem && mySelected[i].id != sourceComp.id){
			destinationComps.push(mySelected[i]);
		}
	}
	if (destinationComps.length == 0){
		alert ("No usable destination comps selected.");
		return;
	}
	for (var i = 0; i < destinationComps.length; i++){
		destinationComps[i].layers.add(sourceComp);
		destinationComps[i].layer(1).startTime = 0;
	}
}
addCompToOtherComps()

I don't know any existing script, but your request sounds simple enough. You'd simply use the respective .add() methods to fire your pre-comp at the selected other comps. The only added difficulty is that you would need to include a check that the first comp you select is the one you add or you create a dialog to pick one or use special naming conventions. If you study a script liek the default comp changer that comes with AE (or any other comp-realted script you can find) you could possibly figure it out.

Mylenium