Fueling throughout an IronMan 70.3-tips???

You really have to experiment for yourself though.  The calorie numbers that work for one person will have someone else hurting.  It depends on your size, temperature outside, how hard you are working and how long you expect to be on the course.  I handle a lot less than the example above -- I'm closer to 200/hr on the bike and 100 on the run.

Do the long rides in training and test test test.

My favorite snack on the bike were bite size payday candy bars!  man, they were so good!!!!

For me  it wasn't necessarily about the nutrition aspects of it, but more of the fact that I can only stand so many gels and gu!  These did not melt and the sweet/salty taste was something I looked forward to, and I also used them when I did my IM.

Some good advice here already, particularly Spudone's regarding the need to experiment on your own, Hot Runner's about reducing intake rates in hot and humid conditions, and the others about practicing during long training sessions.  I would note that Baowolf's 300-350 / hour is his particular strategy, and won't necessarily work for you.  Frankly, that's the high end of what I've seen work well, and wouldn't recommend that high for a starting point, unless you're a really big guy who tends to have an iron gut.  IME, most people perform best at lower numbers, typically in the 200-250 range, and most people need less than they think they do.  Personally, I've raced a HIM on a very hilly course with over 6,000 feet of climbing on the bike and 1,200 feet on the run on a total of only 800-900 calories, and felt great.

A couple other things to think about - Because gastric absorption rates decrease as intensity increases, an effective strategy to practice nutrition (plus pacing) is to do long training rides at a little higher intensity than you'll use on race day.  If it works at a higher intensity, it'll almost always work well at lower intensities.  One of the biggest causes of GI issues during races is a combination of trying to fuel with things and at rates higher than was used in training and/or trying to race at a higher intensity than you trained at while maintaining the same fueling rates.

Fuel at higher rates during the bike than the run.  The jostling and higher intensities associated with running will decrease the rate you can absorb fuel and hydration.

Most people do best with fueling during the bike on a modified bell curve.  Limit consumption for the first 20-30 minutes after the swim, fuel at your highest rate during the middle portion of the bike, then taper off to less during the last hour of the bike before starting the run.  It frequently works best for athletes who fuel with solids during the bike to eliminate them during the last hour and only use liquids during that period.

On a side note, most people who swear that they imploded during a race because of inadequate fueling actually screwed up their pacing, and tried to race at a higher intensity than they were capable of sustaining for the duration of the race.

This is particularly important - when I tried for a HIM (eons ago) the most important aspect of short runs off long bikes was a nutrition check.  Could I sustain an easy-ish pace after a long bike?  When I could answer yes, I knew I had nailed the nutrition (and pacing, of course).   Nutrition must be practiced and decided upon well before race day.

I suggest searching the forum for HIM Nutrition - this comes up a lot, although the answers in this thread pretty much cover it.