I have downloaded following gnu toolchain for cortex m3 and unzipped it but i don't understand how to use it -> http://www.codesourcery.com/sgpp/lite/arm/portal/package6503/public/arm-uclinuxeabi/arm-2010q1-189-arm-uclinuxeabi-i686-pc-linux-gnu.tar.bz2
my computer has windows 7 ,is it necessary to have linux as host computer ??
From my experience doing development for embedded Linux works best with a Linux host. Depending on what you want to achieve you might get along with a Windows host, but it is not the best way.