It's no secret that Google wants Gmail to be a lot more than just your email client, and today the company has taken yet another step in that direction with the introduction of a lightweight to-do list called Tasks for the popular webmail service. To activate it, you will have to go to Settings/Labs in your Gmail account and right at the top you will find the Tasks module.
It's a relatively simple feature, but could prove really useful for those who want way to get organized without leaving Gmail. You can add tasks and reorder them, and of course, cross out the completed ones. You can also convert emails into tasks, in a similar way to Apple's Mail app on Mac OSX or Outlook on Windows machines.
There are still some important features missing. For instance, you can't share tasks with others and the service lacks integration with Google Calendar. Still, it's simple, it's free, it's portable and it works. As a side note, if Gmail Tasks is too lightweight for your needs, then you might want to check out Remember the Milk which also works within Gmail and supports offline usage through Google Gears.