Hmmm... with my new 3GS (O2, UK), in order to even allow me to select tethering on my iPhone I need to set up my account with O2 and pay for their "Internet Tethering Bolt On", as there's already a million threads on this forum saying. However, what if I want to activate tethering but just use a Wifi connection to the internet, not a mobile/cellular one? And before anyone asks why the heck I would want to do this when my MacBook has Wifi and could connect directly, I'll explain: I stay in a lot of hotels, and in quite a lot of these you have to pay extra for wireless internet access. In order to stop guests sharing the same paid-for access, when you first sign in the system logs your MAC, so if any other device tries to connect using the same user ID/password, it fails. I'm sometimes travelling with 2 laptops and my iPhone that I want to connect, and I can't connect them directly without paying for access for each device. However, if I could tether to my iPhone I could use that as a single connecting device. I know you can tether wirelessly, as I hacked my "old" 3G to use the O2 tethering, and noticed that it would use a wireless connection whenever there was one. However, I don't want to hack my 3GS and end up losing MMS or whatever, I just want to be able to *legally* use tethering, but without the O2 bolt-on I don't think I've even got the option.