divide a movie

use hjsplit

You can also cut the movie in ulead movie factory

What is the purpose of dividing?

For storage purpose or to get specific scenes/episodes out of the movie?

for specific scenes

You can start with VLC media player. It is really easy to snip files with VLC.

If you want to cut up specific scenes use video splitters like zealot video splitter or vcd cutter.

FreeStudio is best all-in-one utility

@sharmipriya: use Boilsoft Video Splitter
Pros: No re-encoding,gives output same as the original video,supports wide range of formats
Cons: Not Free.30 Days Trial version

You can use Format factory or Mediacoder for that purpose.