Youtube 3 Quick Questions?

1.) I see all these videos on Youtube of people dubbing their own voices on episodes of SpongeBob and other things and I I wonder how to do that and what you need? 2.) In Youtube there are a lot of random clips of all the different episodes of several television programs. Now I wonder where people find all these specific clips and how to post it on YouTube? 3.) Do you know any editing software free video that is easy to use and works well? If you please post the link. Thanks

Sorry, not a clue: (

Spongebob Squarepants Movie trailer