The wheel is the stock Jalco that Specialized apparently switched to with its 2007 models. The spokes are straight pull, and I replaced the first two. From day one, the wheel makes a subtle creak under a load -- when I'm on it. The noise isn't there just spinning the wheel on the stand. My diagnosis is several spokes are under-tensioned and under a load the spokes are popping out of the hub sockets slightly.
The first broken spoke happened as I was coming home and made a very loud "pop" -- I thought it was the tire hitting a rock. The break occurred about 1/3 of the way out from the hub, and my initial reaction was defective spoke. I replaced it with a spoke from a bike shop close by.
After installing the spoke, and while checking the wheel for true, I attempted to tighten several spokes which seemed loose. Most simple spun around without any adjustment, which is a little annoying. The second break was one of these "adjusted" spokes and in the neighborhood of the first broken spoke -- just above the nipple, and happened while on the road to Denver. The bike wrench in Denver thought I probably damaged the spoke while adjusting it . . .
. . . or popped it while loading or unloading the bike!
The third break happened Sunday. I did not notice the actual break, but as I loaded the bike I heard a rattle in the wheel and realized it was the nipple rolling around inside. I noticed several spokes on either side are loose, although the wheel rolls without rubbing the brakes. So this time I'm heading to the shop which sold the bike to talk warranty/repair/replacement. I've never popped a spoke before, so I'm convinced something isn't right with this wheel.
I appreciate everyone's contribution to this -- it all helps as I get ready to visit the bike shop.