This paper, written by a guy with very good credentials, is the current best bet for a proof that P≠NP. It uses an analogy between solution space complexity and thermodynamic entropy to show that the class of polynomial-time-solvable problems is a proper subset of the nondeterministic-polynomial-time-solvable algorithms.
There are a lot of people getting very excited about this since the guy is not just a random crank but actually has a lot of authority and the paper itself looks very, very good. However, it is a little bit suspicious that many top theoretical computer scientists who have spent full time on this have admitted total defeat and this guy who has a day job at HP managed to get it.
Here are some people discussing possible issues with the proof. I am totally not equipped to evaluate the paper in any meaningful way, but however it turns out this is a pretty big event.