I have been working in a little ACL tutorial this afternoon (http://mumble.sourceforge.net/ACL_tutorial). It uses some images to help the user understand what he is doing. Unfortunately, I haven't been able to upload that files to the wiki itself, so I had to link them from some image hosting service. I think it's better to have them uploaded here, because the images can get removed from the image hosting when they feel like that. I don't know if it's possible to do that; if it is, just tell me where I send/upload them and it will be done :)