One of the big reasons I made the switch to Squarespace was the promise of the forthcoming iPhone app. It's finally here, it's free, and I have to say, it's pretty slick. The only thing you can't do is hyperlink text.
I'm a firm believer that when smartphones really do become pocket computers, the ability to connect and share instantly and untethered will transform the way we communicate. Facebook and Twitter are massive in the mobile sphere already and apps like this will make updating a blog by PC a thing of the past.
Here are a few screen caps (taken with my iphone) to show you how intuitive and fully featured this app is. Once they add hyperlinking I may never blog from my PC again: