WoW UI Tutorial - pvptutorial.com

By popular demand, the second edition of this PvP UI Tutorial contains a section on configuring Power Auras. This addon is very similar to the trigger functions of MSBT, but will allow you to have visual icons that appear for a duration or flash on events. There is much overlapped functionality between Power Auras and Mik's Scrolling Battle Text, but some events you may feel more comfortable having Power Auras deal with. For example, time-duration proc-based buffs are a very good candidate for Power Auras.

You can find Power Auras at Curse.com or Wowinterface.com.

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For a written tutorial covering much of same stuff in this video (if you like to read), check out this guide by Outsourced.

For a hunter-centric guide, check out this video from BigRedKitty.