I would recommend that you start with a mat and some light dumbbells. You can always add heavier dumbbells later on as you get stronger.
You can also search Grokker videos that do not require equipment by going to the Grokker homepage at grokker.com, Fitness Videos, More Options, Scroll down on the Left to Equipment and select None Required. This will bring up all videos that do not require any equipment if you would like to start there.