The tilt on my phone is locked. How do I turn it off?

Tilt lock?

You mean the portrait orientation lock?

Double click home button-scroll to left in recently opened app tray, you will see playback controls-on the left a icon with a circular arrow with a lock in it, press it.

http://timeread.hubpages.com/hub/How-to-lock-the-iPod-touch-or-iPhone-screen-in- portrait-orientation

double click home, slide the four icons at the bottom to the right, and then you should see the tilt lock button on the far left. tap it to turn it off. Then hit home again to escape out