Development - this is simply the process of 'finding' a story. Ideas for films come from a variety of sources, they can range from novels, real life events to computer games adaptations. Once you've got an idea, you'll need someone to write a pitch for you which you take to film producer in an attempt to get some funding to make your film. Even at this stage, you need a very clear idea of who you're aiming your film at so you can include elements that will appeal to them.
Pre-production - Once you've got funding, you establish your budget and can begin to get a film crew together, you can storyboard the script. You also need to break he script down into individual scenes and identify all the locations, props, cast members, costumes, special effects and visual effects needed.
Production - this is simple the process of 'making' the film. Provided you've done your job properly in the pre-production stage, making the film should be straight forward. 'Film' is very expensive and difficult to store so an increasing number of film makers are using digital cameras to save money.
Post-production - during this stage, you take all the 'film' you're shot and give to it a film editor. They will the begin putting it together. Special effects will be added, a soundtrack will be added, any missing dialogue will be re-recorded and added resulting in a 'rough cut'. This will be shown to the director and a test audience who will offer feedback. Often, this causes scene to be filmed and added or removed.