My BFF and I are doing this. Check out
http://www.myfitnesspal.com/ I like it for if I'm out to eat I can pull it up on my Blackberry and search for something good calorie wise. I'm terrible at recording my food but I plan on starting tracking the exercise and water intake. I've lost weight this first week! I use the treadmill for 30-45 minutes 5 days a week. It's nice because I can look at her food diary and exercise and send her a "get on the treadmill text" to hold her accountable and vice versa.