From freelancers, to small shops, to mid-sized companies, to enormous multinationals, Basecamp is a go-to project management tool for hundreds of thousands of groups world-wide. Basecamp helps companies wrangle people with different roles, responsibilities and objectives toward a common goal: finishing a project together.
Basecamp’s at home on Safari (Mac, iPhone/iPad), Chrome (Mac, PC, iPhone/iPad, Android), Firefox (Mac, PC), and IE 9+ (PC, Surface). Basecamp also integrates effortlessly with email. Official apps are available for Android on Google Play, iPad in the App Store, and iPhone in the App Store.
—More info: https://basecamp.com