Crossfit and CFE... questions

Ok, some background for reference. I'm 24 years old, 5'10, 176lbs, around 11% (for real, not made up numbers) bodyfat. For the past 6 months I've been an avid Crossfit'er, probably not missing more than 2-3 workouts total. As of the last two months I've been doing Crossfit endurance as well (3-4 times a week, different disciplines different days) and I usually run at least a 5k - 10k every saturday morning. 23 minute 5k, 52 minute 10k, 300lb bench, 375lb squat, 395 lb deadlift, 285lb pull-up. (max's... again, not internet bragging) Before Crossfit I was a pretty avid bodybuilder (reaching around 220lbs in prime.) and I have a pretty solid grip on nutrition / supplementation, etc... however, most of my experience is obviously in weightlifting,  not endurance sports. 

So I put it to you guys, how drastically should my training change? My plan is to enter a 1/2 Ironman in May of '09, and then a full Ironman when I can. I am a decent biker, poor swimmer (like... barely a step above drowning) and so/so runner. (Not really winded on my 5-10k's, I just don't seem to be getting faster.)

It seems crossfit is well suited for gaining stamina, but I fear I'm going to be in danger of overtraining if I add much of anything to my current regimen. BCAA's only go so far  

Thanks in advance.