Anxiety is a super-lightweight To-do list application for Mac OS X Leopard that synchronizes with iCal and Mail. Its aim is to provide a streamlined, easily accessible interface to add and check off your tasks, while remaining poised to melt into the background at a moments notice.

Anxiety utilizes Leopard's Calendar Store — a new system-wide database that contains your calendars, events and to-dos — to remain in sync with iCal and Mail. Add, remove, or check off a task in either Anxiety or one of these apps, and the changes will be reflected in the others.

Anxiety is perfectly integrated with Apple's other applications that posses to-do functionality: Double-clicking a list item reveals the task in iCal or Mail for extended editing, and simple shortcuts allow you to see your full list externally.

We all work in different ways — let Anxiety's appearance and functionality mirror your own style! From toggling the application dock item and menubar item, to enabling list sorting and setting the list window to disappear when inactive, the choices available allow Anxiety to be tailored to any workflow.

Anxiety's sleek interface provides just what you need to jot your tasks down, without burdening you with cumbersome large windows. With a tiny desktop footprint and clean minimalist aesthetics, the application is simultaneously small, beautiful and effective.

Outfitted with a menubar item that toggles the visibility of the list window and capable of either floating above other windows or subtly fading out when you switch applications, Anxiety is there when you need it and invisible when you don't.