Heather, Holly, and I watched Timeline last Saturday. 
I had read the book, and was excited to see the movie.  Unfortunately, the movie was disappointing.  The book was great, and I recommend it.  Michael Crichton really does his research, and this was very evident in the book.  I am familiar with many of the principles of quantum mechanics, and found myself nodding my head while reading those parts of the book.  While the idea of using these principles for time travel is preposterous, it was an interesting and entertaining take on those principles.  The movie didn't address any of these concepts.  In fact, they glossed over all of the technology that was used in the time travel.  I noticed the absence of Michael Crichton's name on the list of screenwriters, and I think that is one of the problems.  I can safely say that this is the worst film made from a Crichton book since Congo.