Legalzoom.com is a great website. It doesn't teach you how to patent your idea, but it will help you to get the patent. It guides you through the entire process.

Getting a patent is a great idea to protect your idea. You can apply for a patent online www.InventionHome.com.

It's called a "patent" :)

Yes, but as soon as the patent is granted, you can no longer use the idea.

There are many companies out there that will tell you how to get a patent, however, most are scams. You can apply for a patent with the US Patent Office at www.uspto.gov.