Sorry, but I'm gonna have to side with FunkyDerek on this one. There have been numerous experiments performed to try and demonstrate ESP and so far there has been no evidence - not even a hint! Also, there is a million dollar reward out that has never been claimed for anyone who can successfully demonstrate this skill.
From all of the research I've done on this topic, the explanation seems to be human psychology. We remember the hits and forget the misses. We forget how many times we have those feelings that something really bad happened, and then nothing comes of it, but the one time it does happen it is proof positive for us. I have such feelings all of the time, but it is rare that there is anything I can connect the feeling to in real life. Every time I fly or my wife flies or my wife is out later than I expected I get a sinking feeling that something is going to go wrong. Nothing ever happens, but if one day something terrible happens - I could mistake that ordinary feeling for a premonition.
The mind is a very tricky thing. Many times we make much more out of something than it really is if there is some later event that seems to be related to the strange feeling. We can even reinterpret what we remember - memories are not concrete. People can influence the way we remember our experiences and the more times we bring back a memory, the more it becomes modified and expounded on. Details are added without realizing it. After a while, the real memory is forgotten and our new version is the truth in our minds. This is just a fact of how our not so perfect memories work.
There are a lot of anecdotes to support this phenomenon, but no positive quantifiable evidence at all. The same can be said about UFO's and Conspiracy theories. I think it's an interesting reflection of human psychology, though.
rem
p.s.: If some type of ESP were a real phenomenon, then I'm sure Vegas casino's would be bankrupt by now, or at least there would be rules against it. Also, the government ESP projects were all cancelled - I suppose they didn't work as planned.
"Most people would rather die than think; in fact, they do so."
..........Bertrand Russell