For mac users:
Sub Select_Folder_On_Mac()
Dim folderPath As String
Dim RootFolder As String
On Error Resume Next
RootFolder = MacScript("return (path to desktop folder) as String")
'Or use RootFolder = "Macintosh HD:Users:YourUserName:Desktop:TestMap:"
folderPath = MacScript("(choose folder with prompt ""Select the folder""" & _
"default location alias """ & RootFolder & """) as string")
On Error GoTo 0
If folderPath <> "" Then
MsgBox folderPath
End If
End Sub
Stolen from http://www.rondebruin.nl/mac/mac017.htm ;)