Did someone say toggle button? A toggle of course is a control that is either on or off—think light switches, power buttons, and checkboxes. On the iPhone, the only toggle that comes built in is the switch control, a left-right slider that looks like a light switch turned on its side. Just like that light switch, it has two settings: on and off.
Figure 5-37. Switches are commonly used as the right-hand control in standard table cells, as shown here.
In traditional web and desktop interfaces, this on/off job would typically be handled by a checkbox, but there's no such thing in the standard kit of iPhone controls. This switch control is the closest thing on offer, alongside the option to add check marks to list items in table cells (page 153). If those options just won't fit your needs like a checkbox, the alternative is to build your own—a custom button that shows the image of an empty box in its normal state and the image of a checked box in its selected state.