This is the situation:
We have a broadband connection which is shared by 6 people who have different os'es and laptops.
But now we are planning to share movies among 6 people... How to achieve this? I dont have any idea.
One computer will have to act as a network share. A physical location of your movie files. That computer then has to share that folder/directory with the other computers. Depending on the OS of the computer that has the movie files on it, check below for tutorials.
http://www.techotopia.com/index.php/Sharing_Ubuntu_Linux_Folders_with_Remote_Windows_Systems
A bit of an expensive solution, but one which requires minimal setup/administration is a NAS client like the NETGEAR ReadyNAS NV+ (you can find it on Amazon amongst other places). It has 4 slots for SATA hard drives and you can buy just the NAS unit or get it along with 2 or 4 pre-installed 500GB or 1TB disks. This eliminates the need to run a dedicated server just to share movies amongst a couple of people.
Alternately, you could just set up Windows filesharing on the Windows systems and run Samba on the linux/unix systems. This means that you have access to each other's movies/music/whatever, but only when their computer is on.
You could run some p2p sharing within your network. DC++ might be a good choice. You need to make one of the computers a server/hub.