Recently Google added Task in Gmail Labs which will help you to manage your task within your Gmail account . you can not only manage your task in gmail but also in Google Calender , iGoogle and also from your phone by going link to www.gmail.com/taskWatch a Video
http://www.youtube.com/watch?v=qrka_3jui8M
Google also provides task gadget which you can easily add to your iGoogle account. those who never used Google Task before , for those Google Task could be some thing new but for those of you who are already familiar with Task, here are some powers tips to make you more productive.
1. When you have completed a task and no longer want it to appear on your list click " clear completed" in the action menu. you can review your completed tasks later by clicking " view Completed task " Clear completed task is different from deleting them. if you delete a task , it is gone for good and you will no longer see it anywhere in task.
2. In the default " My folder" view , press tab to indent a task your editing, making it a sub-task of the one above. press shift+tab to reverse this operation.
3. Try Ctrl+up/down to move the task your editing up and sown the list . move a task that has sub task , and they will come along with it.
4. Ctrl+up/down also works in sort by date view, where it will alter the task due sate by one day. you can use this to quickly plan out your weeks activities or postpone a task for another day.
5. Press shit+enter to edit the detail of a task , including it's notes and due date . you can also use this view to move your task to another list.
You can also share your view on Google task on twitter .
www.twitter.com/googletask