*Nikki*: Two great resources for information specific to women's fitness I've found are Women's Health magazine and Fitness magazine. Women's Health has a nifty email newsletter with links to online content and also a bunch of workout design tools on their website:
www.womenshealthmag.com
The key with working out is to 1) do something you enjoy, 2) make it a habit, and 3) do more than just cardio. Resistance training of some kind is key to a well-rounded workout. I do both weight training and yoga--my goal is not to be a muscle-woman, but rather to build muscle in order to boost my metabolism.
There are a number of fitness trackers online to use--FitDay, which mal already recommended, and then there's another cool tool from WebMD that is a little more personalized--the WebMD Health Manager.
http://www.webmd.com/health-manager There is a piece of the Health Manager called the LEAP where you can track your activities--every activity is given a number of points based on duration and intensity, and your goal is to hit a certain number of points per week. It's very good for habit-building, and it's also good for encouraging diversity in a workout, because they set you up with a little workout plan after you do the health assessment.