I saw that last night, too! Only just mind - there was a cloud doing its best to cover the sky at that exact moment, but we saw them through the ragged gaps at the edges. There was also the ATV supply ship a couple of minutes before the ISS/Shuttle pair. It was indeed very cool to see them all chase each other across the sky.
http://heavens-above.com/ is a great site which tells you when all kinds of things are visible from your location. Iridium flares are always fun ;-)
They're visible again tonight by the look of it, although a bit further apart in time. Look for them about 20:53 - 22:59 above Austin.