From frozensheep Ltd.:
Online task manager that allows you to plan your tasks so that you never forget the important things in both your personal and work life. You can filter your tasks into keyword groups, color label tasks and track active/completed tasks using RSS feeds.
It includes:Offline mode,Drag and Drop ordering,Inline task editing,RSS Feeds,Smart Tagging,Colored Labels,Completed Items.
Version 1.4 includes Drag and Drop ordering,Inline task editing.