Unfortunatelly (or not) you can't get the plain text password. But you can test the password sending the salt using to create it.
updated: I thing that use the password function is a bad ideia anyway.
Sorry for this useless post, but I read the good answers just after posting it :p .

In reply to Re: Reversing MySQL's password function by r34d0nl1
in thread Reversing MySQL's password function by ralijani

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