Here are a few tips that I've learned along the way...
1. Sign up on beachbody.com. There's some great info on there, you can sign up for a weekly newsletter that will tell you all about the latest products, and the message boards help a lot. I don't go there every day, but it's the first place I go any time I have a question.
2. I completely disagree with some of the comments saying to forget the nutrition plan and just "eat smart". I'm not saying that you need to eat every meal out of the guide and you may know a lot more about nutrition than I did, but understanding what your body needs to be successful is critical and there's a lot more to it than just watching calories. I've gotten to the point where I don't need the guide as much anymore, but it changed my entire diet when I first started.
3. The bands are great for a lot of exercises, but get some dumbbells also. There are some things that you just can't do with the bands and then even some of the times when you can use them, it's still really awkward.
4. Don't ignore the Stretch and Yoga dvds. I can't do every move on the yoga one, but I can't begin to tell you how much it helps with recovery. Let me know how you feel after doing chest/back, Plyo, and then arms/shoulders during your first week. You're more than likely gonna hurt like hell just like everyone else. When you start Yoga on day 4, you'll think that there's no way you can get through it, but then all of a sudden you'll start to feel better. By the time I got done, nearly every pain that I had was gone. It's incredible how much it stretches your body while giving you a decent calorie burn at the same time.
All that said, I'm a big believer in P90X. I worked out at a gym in Jackson for a year and never saw the gains like I have through P90X in just a couple months. If you put a good nutrition plan together and follow the program as closely as you can, you'll be amazed at the results.