You might really benefit from looking through the 3 Fat Chicks book. They review a ton of different diets with information on what works well and doesn't work well with each. They give lots of good advice on what diets work well for different types of people (list of information on "This diet works well for people who:" etc.).
To learn more about SBD, pick up a copy of The South Beach Diet
by Dr. Arthur Agatston. It's out in paperback now, so it's fairly inexpensive, but you can also borrow a copy from your local library. When you've read it, you can supplement what you've read with the info in our FAQ, but you really need to read the book; the FAQ won't give you enough to successfully follow this plan. The book is at least half recipes, so don't be daunted by its length.
If your husband won't give up Pepsi, he wouldn't do well on SBD. If he's willing to switch to Diet and drink no more than 16 oz a day, he'd be okay. But if he drinks more (caffeine issues) or regular (sugar issues), he won't be able to succeed with this plan. He might do better on a plan like Weight Watchers, which allows everything, in moderation, or on a counting calories plan like DS described. However, make him aware that he can consume a lot more calories by drinking them than he can by eating them...so he's literally making it very easy for his body to gain weight if he's drinking a lot of Pepsi. Plus, the caffeine in it causes problems with insulin (leading to fat) in his body and also limits the amount of nutrients his body takes in with any food he consumes while drinking Pepsi.
It's his decision, but he should be informed about what kind of a decision he's making.
Good luck...if you decide to join us, hope you'll participate in the daily thread (the one with the day of the week in the title) and introduce yourself so we can get to know you better!