how long should movies take to download? how do u tell the difference between a preveiw of the movie to a full movie? what about the speed the most is 15 kb/s?

well, big files (like movies) can take a long time, especially if your connections can only deliver 15 KB/s. At 15 KB/s, a 700MB file would take over 12 hours.

A 2 hour movie can probably be squeezed into 700 MB, but better quality would be much larger.