This might come in useful. it converts a text file from the Code Manager from this website to the same type of GCT File that will work perfectly on the wii..Heres the code:
VB.net:
Sub Process(ByVal FilePath As String, ByVal GCTPath as string)
Dim R As String
Dim len As Integer
Dim codes As String = ""
Dim data As String = ""
Dim Reader As New StreamReader(FilePath)
Dim Raw() As String = Reader.ReadToEnd.Split(Environment.NewLine)
Reader.Close()
For i As Integer = 0 To Raw.Length - 1
R = Raw(i).Replace(" ", "").Replace("*", "")
len = R.Length
If len = 17 Then
R = R.Remove(0, 1)
R = Data_Hex_Asc(R)
codes += R
End If
Next
data = Data_Hex_Asc("00D0C0DE00D0C0DE")
data += codes
data += Data_Hex_Asc("F000000000000000")
Dim Writer As New StreamWriter(GCTPath)
Writer.Write(data)
Writer.Close()
End Sub
Public Function Data_Hex_Asc(ByRef Data As String) As String
Dim Data1 As String = ""
Dim sData As String = ""
While Data.Length > 0
Data1 = System.Convert.ToChar(System.Convert.ToUInt32(Data.Substring(0, 2), 16)).ToString()
sData = sData & Data1
Data = Data.Substring(2, Data.Length - 2)
End While
Return sData
End Function