How do you type on your iPhone: Hand position? [Poll]

For the first on this week's series of polls on keyboards and typing, we want to know whether you typically type on your iPhone with one hand or with two? Do you hold it and thumb away at the keyboard with the same hand? Do you hold it in your left and poke away at it with your right, or vice versa? Do you hold it in both hands and thumb away at it? If you use multiple methods, which one do you use most? Do you vary your grip when you want to type faster?

Vote in the poll and let me know the details, and the reasons for doing it the way you do, in the comments.