[amel27]

еще вариант (штатными средствами):

Код:

$s_IEString = "http://ru.wikipedia.org/wiki/%D0%92%D0%B8%D0%BA%D0%B8%D0%BF%D0%B5%D0%B4%D0%B8%D1%8F:%D0%9F%D1%80%D0%B5%D1%81%D1%81-%D1%80%D0%B5%D0%BB%D0%B8%D0%B7%D1%8B"
ConsoleWrite(_INetExplorerCapableUndo($s_IEString) &@CRLF)

Func _INetExplorerCapableUndo($s_IEString)
    Local $a_IEChar = StringRegExp($s_IEString, "%[[:xdigit:]]{2}", 3)
    If IsArray($a_IEChar) Then
        For $i=0 To UBound($a_IEChar)-1
            $s_IEString = StringReplace($s_IEString, $a_IEChar[$i], Chr(Dec(StringTrimLeft($a_IEChar[$i],1))))
        Next
        $s_IEString = BinaryToString(StringToBinary($s_IEString, 4), 4)
    EndIf
    Return $s_IEString
EndFunc