Time estimates. If all goes well you could have your first movie shot edited titled credited and uploaded onto YouTube within half an hour. Getting to your first Oscar.... may take a little longer.
This is a movie editor which comes free with windows. Video clips from video cameras, mobile phones, and other sources can be combined and audio can be added, and still images can also be used.
How to get started:
there is a good webpage here:

from Microsoft, which leads you step by step through the process.
I have a short video on downloading and installing this program here:
A video on downloading and installing windows Moviemaker though you probably have it pre-installed on your system already!
Although video clips from a camera seem an obvious input, you can also use the output of MonkeyJam, the animation program discussed here and still images, adjusting the length of time the still image is on the screen within the movie editor.
Note: if you need "Green screen" as a feature, the inexpensive, but not free, PC based, Pinacle Studio has been recomended to me.

Other platforms:
Apple: Here your choice is Imovie. There is a link here: comes free with all new Mac's and can be bought as part of ILife for around 79 Euro's for older Mac's. One advantage of this product over Movie maker is the ability to combine vieo footage using "Green screen" which is a method for floating one image over another. Think: Image of your self talking about the ocean floor while floating in front of underwater images of fish.
Web based:
You could try Jaycut at YouTube also allows some limited editing to be done.

Educational use.
Automating a slide show, putting a slideshow together with narration, group work, packaging a video based student assessment i.e. editing it down to the critical parts and deleting all the “are you ready now?” bits.. Subtitles can be put on slides or video clips (use the title option and then set the location to the bottom of the screen). A short video could be part of a quiz, or could be a method of recapping what the class saw on a school trip. Video could be used to showcase student work, and can be posted to Vimeo or Youtube. I find my primary use for it is in blended learning, where I ask students to preview material which we will be covering in the following class. An example of this would be mathematical procedures, where I show students how to perform mathematical operations in a video, and then work with them in the following class to complete examples of the task.

User Survey
I'm interested in knowing who comes to this site, and how they use it. I have a short (8 question) user survey here, if you have the time.:
User Survey

Any questions? I have set up a discussion forum for movie maker here:
Eleven Tools Movie maker discussion forum