The port of Unix tools cygwin provides for Windows user is simply awesome, a real need for developers who use Windows nowadays. Fink seems to address the same needs for Mac OS X users:

The Fink project wants to bring the full world of Unix Open Source software to Darwin and Mac OS X. We modify Unix software so that it compiles and runs on Mac OS X ("port" it) and make it available for download as a coherent distribution. Fink uses Debian tools like dpkg and apt-get to provide powerful binary package management. You can choose whether you want to download precompiled binary packages or build everything from source. Read more...