At Marginal Revolution, Justin Wolfers suggests, and at Midas Oracle, Eric Zitzewitz suggests, that someone has been manipulating the Intrade markets to make Hillary look good – Intrade now gives Hillary a 77% chance of winning if she is nominated. If that seems too high, trade accordingly.
Added: Koleman Strumpf says it is 65% now, other markets have similar estimates, and maybe it represents real info.