It's called PowerAuras. Very cool, very handy, VERY customizable.
Linky:
http://www.wowinterface.com/download...owerAuras.html
I really dig it, I've it set up on my pally to display texture-reminders when judgement is ready to cast again, when my blessing expires, when I have a seal active (so I don't forget to refresh), and when I'm cleanse-able. For my 'lock, I get giant purple textures for backlash/nightfall procs, more subtle one for fel armor, etc.