A Backgrounder on aircrack
Page from 2010
Updated Dec 2014
Full instructions and to download the executables for Aircrack for Windows 7/Windows 8.
aircrack-ng is basically a command-line tool that was developed on a Linux platform. However, you can run the aircrack modules on Windows and other operating systems.
To run aircrack-ng on Windows you will need to download the executables that have been compiled for Windows platform. You will also need to be able to locate the correct drivers for the hardware that you are using. Drivers for wireless adapters (NIC - Network Interface Card) that will allow the injection of packet data are far more available for the open-source Linux plaform. This is not to say that you cannot launch an attack from Windows but you are probably better off finding an alternate solution if you are serious about wireless penetration.
There are also many GUI tools that are availble for you to run aircrack-ng on your Windows, Mac or Android hardware.
MUSE Technologies has a full set of executables for Windows XP, Vista and Windows 7.
For those of you that have no Linux experience and have no desire to learn (that is why you probably bought a Windows powered netbook [or laptop] in the first place) a Windows tool is probably more use to you.
Aircrack is only one of many tools that can be used for WiFi auditing. If you are running Windows there may be better and certainly easier programs to install and use.
You can run aircrack-ng (airoscript) from a VMWare Player virtual appliance using any version of Windows as a host.