Any.Do (To Do List) is a brilliant web based task manager & to do list.  As its web based it integrates with a wide variety of web based devices and online services.

If you are a busy educator (who isn't?) that struggles to keep on top of all the things you have to do in your day, then you should certainly give a try.

Alternatives to

If isn't for you, you may like to check out some of these alternatives: