Quoted:
If you haven't done this before (triathlon), you need to start working on it now for next year for the sprint level (usually 400-800 yard swim, ~15 miles bike, and 5K run-any discipline's distance can vary a lot in these numbers at the sprint level).
The vast majority of people find the swim the most difficult of the 3.
While people have gone from zero to ironman in 1 year, I don't recommend it unless you are really really fit in all 3 disciplines and can dedicate hundreds and hundreds of hours to training. Swimming in open water is WAY different than a pool swim.
Locally (south central WI), I think the only tri left this year is the McFarland family fun festival sprint. Its a pool swim tri. There are some duathlons (run, bike, run) still going on.
Tri's are not to be undertaken lightly, not even sprints. You may be able to do all 3 sports, but stringing them together one after another is tough.
Books: "Triathletes training bible", 3rd edition. This should be the one you buy. There are a lot of tri books in the library system, but buy this one.
Websites: "Beginnertriathlete.com". Highly recommended. Has state forums also. Don't let the name fool you. Lots of ironman experienced people on here too.
I was a volunteer this year at ironman, so the sag wagon on the bike route. The looks on peoples faces on the 2nd round...man, talk about effort and misery.
I did the half ironman in lake geneva already, and have done madison marathon, DC marine core marathon(did not train for that one as i broke my foot 3 months before hand), lake front matathon, and two mock marathons that i did while in the north woods while training for my 1/2 Ironman.
at a minimum i plan on devoting 15 hours a week to training, realistically closer to twenty as weekends will be long distance bike rides and runs.
i saw the look on peoples faces at mile 90 of the bike... some were still coherent, while others were pretty destroyed.
i have a lot of work to do, so on that note its time to go for a 30 mile bike ride...