I've been a member for quiet sometime, and I feel I have not contributed much, so I will provide the news that for Indonesian iphone3g owner, you can safely upgrade to 3.1, mms and tethering still works fine. Before upgrade, my friend and I, use the benn hack and custom ipcc, after upgrade my friend, need to restart the iphone and after that the tethering works, for myself using custom ipcc, don't need to restart, directly works.
Hope it helps
Hope it helps