To setup a reminder on your note, tap the clock icon at the bottom right of your open note. You can also then select a date for the reminder to appear with a slick animation appearing to help you set the time of the reminder. Reminders also appear at the top of your note list.
I especially like the swipe right to mark as done and the swipe left to change the due date options on my iPhone 5. Evernote offers up some examples of reminder notes, including birthday gifts, project planning, packing lists, and doctors orders. I am excited about the reminder functionality and look forward to the rollout on Android and other platforms.