This code might help,it's speed will depend on the number of sheets
Code:
--------------------
Sub SortSheets()
Dim I As Integer, J As Integer
For I = 1 To Sheets.Count - 1
For J = I + 1 To Sheets.Count
If UCase(Sheets(I).Name) > UCase(Sheets(J).Name) Then
Sheets(J).Move Before:=Sheets(I)
End If
Next J
Next I
End Sub