Lots of athletes who need both strength and endurance are turning to kettlebells these days. Read more at my little web site on the subject:
http://www.kbnj.com
They're cast-iron cannonball-shaped things with thick handles that you lift and swing. The main sizes are 36, 53, and 70 lbs. (16, 24, and 32kg) and you do things like a swing-style one-armed snatch for reps - works your whole body. Kettlebells will let you stay strong without adding unncessary bulk and will help, not hinder, your endurance.
If you're looking for specific swim/bike/run training programs, try the news:rec.sport.triathlon, or just Google on 'triathlon training programs' and you'll get a lot of hits. Here's but one web site for you:
http://www.trinewbies.com.
For most people who don't come from a swimming background, the swim is their worst skill. If this sounds like you, get some swimming instruction before you start putting in the hours of practice - the local YMCA is a good place to start, as is a local Master's swim team (ours is at our local Y).
Generally speaking, you will want to train in all three sports by putting in the same total time at the same relative effort, but you should gear your training to the kind of triathlon you want to enter. If the tri distances you'll cover are short, there's no need to go for an 90 minute swim when you only expect to be in the water for 30 minutes at the actual event. The trinewbies site is packed full of training programs so you should be needing anything more than that to get yourself started.
