A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
rhodesmk,
You can apply the emphasis effect blink. In the custom animation pane, click add effect, emphasis, more effects, you will find it in the exiting section. Once you have applied the effect, double click it and on the timing tab next to repeat set it to repeat till next slide or till next click whichever suits you best.
Luc Sanders
MVP - PPT