Gmail and google calender have a task module which allows you to create lists for various tasks (homework, shopping, todo list, etc.). If you set a deadline for your task it shows up in your google calenender and you can set a reminder which is sent to your mail inbox or to your phone via sms or via status update.
There are various apps that sync with google tasks. One of the most popular ones is GTasks (shown in the picture). Using such an app you can use your phone as a mobile notebook that syncs with google tasks.
So you can use your laptop or PC to create lists for:- homework
- revision lists
- cheat sheets (e.g. vocab)
- project tasks
- jotting down ideas on the go
and for whatever you use lists.