C25k......how/what/where???

This may be a dumbe question but, I have heard everyone talking about this c25k. I have tried google and other search options, it tells me it helps to get people running, but how do you get it and where do you get it? I want to start trying to run. My mini goal now is to run a mile without stopping and need some help getting it going. I am a 300 pound girl so it will take some time to get accomplished but better late than never right.