GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
Atlassian JIRA - Atlassian JIRA is a project management and tracking software for the business users, developers, programmers, etc.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Assembla - Integrated, on-demand tools to build software faster, with less stress. Get started for free and find out why over 800,000 users trust Assembla.
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
Pivotal Tracker - Pivotal Tracker: The awesome, lightweight, agile project management tool for software teams. Get your 30-day Free Trial started today!