If you find the reminders app in iOS 5 a little too basic, free to-do app Astrid might fit you better. its social and sharing features set it apart from other task management apps; you can manage your tasks by creating lists and adding tasks with priorities, notes, and reminders, but you can also easily share these lists or tasks with others using Astrid. You could share a work to-do list with a project team, a home list with your spouse, and keep any other lists you need perfectly private. Users can comment on tasks shared with them, so if you need to send someone details on a task (like a phone number or email address) it can be easily done right in the app, linked to the appropriate task.
This app also works across platforms — Astrid was originally an Android app, and there's also a web interface for managing tasks away from your phone. While Astrid is certainly more feature-filled and social than Apple's Reminders app, it doesn't offer location-based reminders. Many users may stick with Apple's default remindersa pp, but Astrid's collaborative features and price should help it find a new audience on iOS.