The Kona Rating Report is the best resource to look forward to the Ironman World Championships and to follow the race! It's a 130+-page PDF with information about the race, all Professional participants and their chances on October 6th (Pro Women) or October 8th (Pro Men).
The report is available for free (just enter 0 in the "Name a fair price" field you get after clicking "I want this"). However, if you like the report and want to support my work during the season, it would be great if you can send me a few bucks. (For comparison, back when there were triathlon magazines they used to sell for about $8.)