Decrypt Wep

It it any program or plugin that can decrypt wep when I'm using AiroPeek? How do I use it?

i personaly don't know about this but i've found this article:
if you go to http://www.ig.com.au/AiroPeek.htm
it says that airopeek can decrypt wep algorithm but it needs the wep key...

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"Knowledge is the Real Power"

Yes I know but how do I crack the wep key?