How Loud?, Measuring Loudness (Decibels) Options

[korektphool]

HI ALL!
This is what I want to do:
I have a sample (AIFF, mp3, whatever). I want to measure how loud the sound is, in decibels. Is there an application that can do this? Or is there a VST instrument that can do this once I load the sample in Cubase?
All help is appreciated.
PS In case you are wondering why I would want to do this, it is for a science project (I go to school).
Raghav Kaushik [KorektPhool]

[sethjacquay]

Jeff,

Question, I have read the term VU time after time
in the this mastering book I am reading.
What, in the "name of Starbucks", does that mean?
Volume Unit?
Voltage Unit?
Voltran Unlimited?
Vulcan Unix?

Also, is there any standard at which you can measure not really
the loudness of the recording, but the level of the signal?

There really should be considering anyone can draw comparsions
using the AIFFs they create themselves and the AIFFs on mastered CDs.