Reminderz allows to create "snoozable" reminders.
All the reminders you defined will be reminded with the option to snooze them.
Should you be doing something else when reminded about your task, never mind just close the popup message, Reminderz will popup again.
The reminders will pop up even if the application is closed. While within the app, the reminder will play a beep alarm and vibrate if configured to do so.
Requires iOS 4.0 or higher.