http://www.youtube.com
Click on "Upload"
It will probably make you register, just fill out the fields, and follow the instructions they give you. Its really simple. After you register and log in, click on 'Upload' again. Now you'll see this screen:
Fill out these fields with whatever you'd like to describe the video. Click the "Autos & Vehicles" checkbox. Then click "Continue ->"
Now click 'Choose' in the blue box, and select the clip you'd like to upload. Then just click the "Upload video" button, and leave it alone for a few minutes. It'll take a little while for the video to transfer, and once it does it the whole screen will change to something saying your upload was successful.
Good luck and let me know if you have any questions!