I have been using iPhone tethering for almost a month now, and it rocks. I am not going to update to any new iPhone OS unless I am sure I can tether.<p>Paying $45 for HSI at home and $30 for iPhone is a lot. I am not looking forward to add more to it for tethering.
Beware: You will probably lose your Visual Voicemail.<p>But that's okay: Try using PhoneGap instead. Works well for me; it sends transcribed voicemail messages to your e-mail.