Reminder Commander - Reminder manager that reminds you about important events in advance.
System Scheduler - System Scheduler for Windows, Free Task Scheduler Software replace Microsoft Windows Task Scheduler
Memo to Me - Online email & SMS reminder service.
VisualCron - VisualCron is an automation, integration and task scheduling tool for Windows.
Date Reminder - Date Reminder reminds you of recurring or nonrecurring events, like birthdays, bills to pay...
Freebyte Task Scheduler - Freebyte Task Scheduler, freeware for Windows and Linux/Wine.