Fortunately, I called up the folks at Tri-California immediately, explained the situation and they were kind enough to refund the entire $285 entry-fee.
Even so, I'm disappointed. For a few seconds there, I was totally psyched to test my mettle in three week's time. There's still Auburn, though I'm not totally sold on doing that one again, and Bay to Breakers. We'll see.
UPDATE: Well, I didn't win the Kona lottery. I had been keeping my fingers crossed that I'd somehow snag one of the 200 available lottery spots for a chance at tackling Ironman's biggest race. Alas, it was not meant to be. I'll try again next year!