Google had introduced an experimental feature dubbed Tasks for Gmail through Gmail Labs six months back. Now, this experimental Task feature has come out of Labs and is available to all Gmail account holders by default.
Tasks is a Gmail feature designed to help you keep track of the things you need to do. You can create lists of items, set due dates and notes, and even add Gmail messages directly to Tasks.
You can access this feature in two ways: either click on the "Tasks" link below "Contacts" to open a Gmail Chat-like dialog or create a task from an email by opening "More Actions" drop-down and selecting "Add to Tasks". When you convert an email to a task, Gmail keeps the message's subject and places a link to the mail.You can also easily convert emails into tasks: select one or more messages and go to More Actions > Add to Tasks
* Open the tasks box by typing g then k if you have keyboard shortcuts enabled.
* Create a task from an email by pressing Shift+T if you have keyboard shortcuts enabled.
* Navigate between tasks using the arrows.
* Delete a task by deleting the text and hitting backspace.
* Organize your tasks by indenting them — just hit Tab to indent and Shift+Tab to un-indent.
* Ctrl+Up moves a task up the list and Ctrl+Down move it down.
* Hit Shift+Enter when in a task to show its details