There is a massive amount of information available about the upcoming Presidential party nominations. Most of it is just noise. One way to clear the clutter and see who is actually gaining or losing ground is to visit the University of Iowa political markets (better known as the Iowa Markets). From the web link below you can call up a graph of the trading prices for each nominee. In this market, investors trade nominees just like stocks. The nominees trade between $0 and $1 per unit. With the winner taking the $1 and everybody else losing.
http://www.biz.uiowa.edu/iem/markets/data_nomination08.html
There is also a trading market on who will win the election, i.e. a Democrat or a Republican. After the National Convention a trading market will open for each candidate.The Iowa Markets were started in 1988. The first traders were a handful of young white males from around Iowa City. Even from such a small group, the Iowa Markets were surprisingly accurate. More accurate, in fact, than the major polling agencies like: ABC, CBS, Gallup, etc. It is surprising to see how accurate markets are when people have money in the game vs. getting a phone call and expressing an opinion to a pollster. Today the Iowa Markets have considerably more traders and have become influential on a national level.