Aircrack-ng Main:

Project Homepage: http://www.aircrack-ng.org/index.php?title=Main_Page

Aircrack-ng is the next generation of Christophe Devine's excellent aircrack suite of tools. 

Installing Aircrack-ng:

Download latest stable code (currently aircrack-ng-0.4.tgz) from http://www.aircrack-ng.org/index.php?title=Main_Page to /tools/wifi

cd /tools/wifi

tar zxvf aircrack-ng-[version].tgz

cd aircrack-ng-[version]

make

make install

It is currently early days for the project and there is currently no major differences between the original Aircrack-2.41 and Aircrack-ng-0.3.  As soon as differences appear they will be highlighted here.

Original Aircrack-2.41 guide