David Hodgson of Prima Game Guides wrote the official guide for Fallout 3 and has previously posted a couple of updates on the Bethesda Blog about it. Since he's also writing New Vegas' guide, he's once again blogged about it:
The Training section is familiar to those who have utilized the Fallout 3 official guides. While much of the way you create your character remains the same, a lot has changed, and flagging each instance with an icon for easy reference was important. After an overview of Attributes and Derived Statistics, there's a section on Skills, including the all-new Survival Skill, and tweaked Guns Skill, which folds much of the Big and Small Guns Skills into one, and provides a Strength rating for each weapon (which, naturally, are given for everything you shoot). Traits are covered, along with advice on picking the ones best-suited to your play style. Then comes the text tsunami known as (Perks), which lists every single one of them. Although I can't spoil your anticipation of Perks just yet, there are some memorable, amusing, and astonishing accoutrements you can add to your Wasteland warrior. The blog post also contains two new shots, one of a rather odd-looking power armor and ramskull helmet combo.
How's your social game? Interacting with Factions, whether it's helping them out, or massacring their forces, affects your adventure in many different ways, especially if you're dressed in specific attire.
The rest of the Training deals with creating a character that isn't going to collapse after a Fiend sneezes on you. How all of the Attributes, Skills, and Perks interact with the clothing you wear and the Followers you find are all extremely important (and overwhelming), so a special Character Archetypes section was created. No matter what your play-style from the social outcast Sniper to a mountain man bred specially for Hardcore Mode there's a character for everyone. We even included the best weapons, outfits, Perks, Skills, Implants, and Followers to compliment each Archetype. One Bethesda employee was said to remark (that's pretty freakin' sweet.) Speaking of Hardcore Mode; the training continues with advice on thriving in this most inhospitable of climates. Then there's updated information on Karma, mapping, and other activities before we delve right in to Reputation, and explain exactly how everyone reacts to everyone else, and how you fit in. What is initially confusing political and societal idiosyncrasies is broken down into something understandable; and more importantly, something you can act on during your entire adventure.