I am assuming this is in the controller of the view with the text field and that it isn't a table view.
Code:
self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y - 100, self.view.frame.size.width, self.view.frame.size.height);
Notice where I subtract 100. That would move it 100 pixels up. Find a value that works well for your view. Add that same value back to origin.y when don and your view will move back down. Throw some animation code around it to make it move smoothly. I have found the keyboard pops up and down in about 0.25 seconds if you want the timing to match the keyboard.
