The Metasploit Framework is released under a BSD-style license. See COPYING for more details.
The latest version of this software is available from https://metasploit.com/
Bug tracking and development information can be found at: https://github.com/rapid7/metasploit-framework
API documentation for writing modules can be found at: https://rapid7.github.io/metasploit-framework/api
Questions and suggestions can be sent to: https://lists.sourceforge.net/lists/listinfo/metasploit-hackers
Generally, you should use the free installer which contains all dependencies and will get you up and running with a few clicks. See the Dev Environment Setup if you'd like to deal with dependencies on your own.
Metasploit can do all sorts of things. The first thing you'll want to do
is start msfconsole, but after that, you'll probably be best served by
reading Metasploit Unleashed, the great community
resources, or the wiki.
See the Dev Environment Setup guide on GitHub which will walk you through the whole process starting from installing all the dependencies, to cloning the repository, and finally to submitting a pull request. For slightly more info, see Contributing.