Begin for iPhone is a brand new iPhone task management app that is very reminiscent of Clear. The interface is a little bit more sophisticated but gives you the same gesture driven controls we've all come to know and love.
In order to mark a task as done, just slide your finger to the right over the item. Sliding your finger to the left will automatically put the task off until tomorrow. There are no other lists to manage or sections. You basically have two options when it comes to sorting tasks. Do it today or move it to the tomorrow section. It will then become due the following day.
Begin was designed with one handed use in mind so all the gestures you use can easily be performed without two hands. Task entry is also quick and lets you add multiple items quickly. Pulling up from the bottom of the screen will show you all tasks that aren't completed yet from both of your lists.
If you're looking for a minimal task app that deals with short term items instead of long term folders and projects, I'd recommend considering Begin for iPhone.