Has anybody seen De Ja Vou yet? I did, and it's very cool! It is confusing, but I think it's worth watching. It's important to pay attention to details, though.

(This part contains spoilers)
 I found the lack of scientific explanation to be quite funny. They did a pretty good job with a simplified summary of quantum theory, which is an essential element to the plot, but how did they create the 'Bridge' that allowed them to view and send objects to 'the past'? Their explanation went something like this-"Well, we were experimenting with the satelites and accidentally made a device that allows us to look into the past four days. It was a complete accident. A fluke." Right.... 
I don't hold that against them, for almost every science fiction movie skips the 'scientific' part. For example, in The Hulk, when Bruce is asked how he managed to survive an impossibly high level of radiation, he replied, "It's the nanomeds. They must have, like, fixed me." Oh, of course. The nanomeds.

Anyway, besides that it's a great movie. However, there was some confusion- they didn't really explain that 'the past' was not really the past- it was a parallel universe that existed four days before the first dimension ( the one that the movie opens with). This confused me at first, especailly because all of the alternate dimensions seemed to be conected. (i.e. the ambulance, the crime scene, ect.) As the movie moved along, I realized that they were riding on the multiverse theory- the universe is constantly splitting into almost identical dimensions existing simultaneously but at differant times. The differances between each dimension is choice. Let's say there's a 50/50 chance that lightning will strike a particular person. The universe divides- in one universe, the person is struck by lightening, and in the other, the person is not struck by lightening. Identical dimensions, except for the differant 'choices' that each one made. 
 (For further explanation of quantum theory, reply to this thread- or better yet, read the book "Timeline" by Michael Crichton, where I first learned about all this confusing stuff.)

Well, hope you enjoy the movie as much as I did! And if you don't understand it completely, don't worry- nobody really understands quanum theory, not even the quantum physicists.