iOS 4.3 and iPhone 3GS: cable and Bluetooth tethering work!
Update to our previous iOS 4.3 post: iOS 4.3′s new Personal Hotspot works on iPhone 3GS – albeit only with cable and Bluetooth pairing!
Long-time friend Enrico has just tested iOS 4.3 on an iPhone 3GS and checked that Personal Hotspot, the internet connection sharing feature of 4.3, runs happily although only via the iPhone cable or a Bluetooth-paired connection.
So, as far as we know, Wi-Fi sharing is available only for iPhone 4.
As a result, iPhone 3GS users can still enjoy their beloved toy and share connectivity to iPad (non-3G) or iPod touch (or any other BT-enabled device, by the way!)