Custom Alert Dialog Boxes

I've implemented a field on an item record that allows for a notice to be entered.  When said item is added to a sales order or quote, it pops up a javascript alert() type dialog with the notice.

The problem is, sales people entering alot of orders on a daily basis are over inundated with alert()'s already due to available quantities, etc.

I would like to use a custom dialog for these rare notices so that they will grab the sales person's attention.

I see there is a DHTML type script embedded somewhere in the JS files to give notice of timed out sessions (dimming the background), and wondering if there's a way to reuse said code instead of having to figure out how to draw in extra .css files via javascript for ready made dialog box scripts available online.