Code Academy: http://www.codecademy.com/ Harvard's CS50 course: https://cs50.harvard.edu/ You can also take CS50 through edX, which grants certificates: https://www.edx.org/course/introduction-computer-science-harvardx-cs50x#.VJjeyf8AAA

Learn Python the Hard Way is a pretty solid resource, though I used it before Codecademy came out. Both are excellent practice-based resources for starting programming. After that, just get python books and work through them. Tools like Flask and Django if you want to do web development, other stuff if you want to do other stuff. If you don't know if you Stackoverflow is usually where google will take you when you look for answers to your questions, so you might as well bookmark it. And if you don't have something in mind you want to make, but you want to keep practising, try doing some ProjectEuler problems.