What is Copyright?
It is a law that protects peoples creative works such as art, music and creative writing and intellectual property such as inventions and designs used in commerce.
It has to be something you created or something you came up with. It also has to actually exist. Your idea for a logo cant be copyright until you actually create it. The reason for the laws are to ensure that people who create things like music and art get paid for their creations. Therefore, to be enforced the work must be worth something.
How do you get it?
Create something. You do not have to go somewhere and get your work a copyright. Students sometimes confuse patents and trademarks for copyright. If you see the copyright symbol on something that is just to reinforce the fact that it is copyright. You should assume everything is copyright unless you know otherwise.
What is Fair Use?
You are allowed to use copyrighted materials for education, satire, news reporting, comment and research as long as you are not making money off them or distributing them in any way. For example, if you use someones photos in your work while learning Photoshop it is fair use. If you sell copies of that work, you are breaking copyright laws and technically stealing from that photographer.
Even if you got them on Google? Yes, especially if you got it from Google.
What if I want to distribute or sell my work?
You have a few options here. The absolute best way to get images for a project is to take them yourself. You cant go wrong if you own the image. Unless you are a terrible photographer or have no access to the shot you want or need. If that is the case you can either find Royalty Free photos or photos that the owner has given permission to use freely. I have a few of listed on the Links page. Or you can pay for photos on a stock photo site.
Visit the Creative Commons web page and watch the video.
A great Wiki dedicated to clearing up copyright confusion.