Lets you communicate securely with people you've never met, with no secure channels needed for prior exchange of keys. Excellent user documentation.
Source code is free.
Read the reasons why YOU need PGP . The Generic Source Code is also available. PGP is written in American English, and has been translated to many other languages . Dependant on which version of PGP you use, it will come in American English, plus possibly two or three other languages. If your native language does not come with PGP, individual language modules are available.