Pomodoro Timer

Forest is an app that helps you stay focused on the important things in life.

Cold Turkey is a free productivity program that you can use to temporarily block distractions so that you can get your work done!

A simple and customizable pomodoro timer for the web

freemium

More suitable with Google Chrome, this service enables you ensure you do not waste precious time on updating Facebook status or chatting with people.

V2 updates! - Custom time interval for distraction free mode - Ability to turn off ' always on' mode - Improved UI -- Self Control -- A simple app to keep you focused online by blocking sites that you spend way too much time on.

Open Source

Freedom is a productivity hack that lets you block apps, websites or the entire Internet on iPhones, iPads, Windows and Mac computers.

With so much access to information and distractions on the internet, it's easy to get sidetracked.

BlockSite is an extension, which automagically blocks websites of your choice.

Pomodone is the easiest way to track your workflow using Pomodoro technique, on top of your current task management service.

Simple Pomodoro timer in your Mac's menu bar

Yellow Tomato is a powerful Chrome extension that helps you implement the Pomodoro technique.

Open Source free

Todoist is a to-do list that helps you get organized, at work and in life.

AntySocial Windows Software blocks access to websites like Facebook, YouTube, MySpace, Hulu, Digg...