If you like you Windows 7 in Quechua spoken across South America and the official language of Bolivia and Peru, then download the latest Windows 7 Language Interface Pack (LIP) now.
Download the Quechua Windows 7 LIP via the Microsoft.com Download Center.
Please note that the Quechua Windows 7 LIP can only be installed on a system that runs a Spanish client version of Windows 7. It is available for both 32-bit and 64-bit systems on the Download Center.
You can download the Windows Vista Quechua LIP (and many others for both Windows 7 and Windows Vista) and it is also available for Windows XP
update 17/12/2010 – added a video of how to install the Quechua LIP created by my colleague Jon