Pulsating LED?

I am looking for a solution I can buy to get a pulsating LED like the ApplePpowerbook sleep mode’s blink. I want to put it in a model and have it look like the red eye in Dave from 2001 Space Odyssey. Any advice? I know nothing about electronics. Hoping for a solution that can be battery powered and can be bought off the shelf.

I think this is exactly what you want:
http://www.cowlacious.com/LightProd.htm

This is cool, but requires AC power:
http://www.ledholidaylighting.com/high-power-color-changing-led-light-bulb-fast-and-fade.aspx

Mathmos makes a bunch of battery-powered ones: