While typing on the iPhone is an arguably difficult / easy process depending on who you are, I figured out a handy tip for saving at least one button press - as long as you're going to a .com site. Just like a real browser, it appears that the iPhone will allow you to type in most .com URLs without having to type the actual .com or pressing the button. Simply press Go after typing the site name and MobileSafari should automatically insert the .com for you. It's worked in every site I've tried so far at least. A mere savings of one button press to be sure, but in my opinion, shaving off even one repeated key press can amount to a lot of saved time after a while.