Any Free CAD Design you can recommend?

[MyDigitalpoint]

I'm not an architect but I have always been enthusiastic to design floorplans and all what is involved in CAD designing.

A friend of mine asked me to help with the project to build an animal shelter and I would gladly like to do it, but being able to design over the paper sheet, my friend lives in other country and it would be easier send her the files to see than the blueprint via snail mail.

Just wondering if any of you can recommend me a good CAD freeware program to play with.

You help will be much appreciated :)