Here's a list of "superdelegates" to the Democratic convention, both those who have already committed to a particular Democratic candidate for President and a link to those who've so far not committed. Why is this important? Because with all the hoopla about the Democratic caucuses and primaries (which so far have Clinton and Obama about tied for delegates, with Edwards behind), these "superdelegates" aren't the result of those processes. Instead, they're Democratic insiders: elected or formerly-serving Democrats, higher-ups in the Democratic Party, and the like. They make up almost 1/4 of the total delegate voting power at the convention, and when these are counted, Hillary Clinton leads Obama and Edwards by a huge margin. These "superdelegates" were the product of "reform" of the party in the 1970's, which allowed these leaders a lessened amount of votes in exchange for expanding the power of grass-roots caucuses and primaries.
Certainly, the reform was an improvement over the back-room deals the Democrats used before for choosing presidential candidates, but there's still a heavy loading of the voting in favor of traditional power--in this case, the Clinton dynasty.