Want your to-do list with you at all times? How about checking things off your errand list while in the store? iDo is a to-do list manager that uses the Getting Things Done (GTD) approach. Using iDo you can easily organize your to-do tasks into projects and contexts. The best part is, you get to use your iPhone. But dont worry, when youre back in the office, you can use your desktop browser with iDo too.