Preparing SD cards from windows
The various .img files can be flashed to SD cards from Windows easily.
Download an appropriate image. A list of available image files can be found on the Images page.[todo create image page]
Some of these image files are provided using the BitTorrent protocol. If you do not have a BitTorrent client you can get one from http://www.qbittorrent.org/ [redundant - move to inside the images page]
You will need a third party utility to flash your SD card. Download "Image Writer For Windows" from https://launchpad.net/win32-image-writer You will need an SD card reader and an SD card of suitable size. 4GB should be enough for most images. Suitable SD cards can be found at http://raspberrypiwifi.com
Preparing the image.
If the supplied image file does not end in the .img extension, it is likely compressed in some way. To decompress the image you will need a decompression utility such as 7-zip available from http://7-zip.org
Flashing the SD card
Insert your SD card into your card reader and ensure that it has been assigned a drive letter by Windows. Open the "Image Writer For Windows" and browse to your image file which should now end in the .img extension. Choose the appropriate drive letter and click "write". After a short while your SD card will be ready and bootable.