Trademarks and Copyrights.
So you've put all this work into your business: you've got a name, you've made some marketing materials, even written some things for your customers. If you don't want your competitors to be able to take what you've done and exploit it, though, you're going to need to take some steps to protect yourself.
What's in a Name?
Your name is one of the most important assets your business has -- it's how your customers identify you. Knowing your name is the first step to trusting you and recommending you to others. But what can you do if you're afraid that someone else might start using your name, or simply start another company with a similar enough name to confuse people?
The answer is that you can register a trademark. A trademark is a word or logo that distinguishes one thing from another, and you have the right to register any names or logos your business uses, in order to stop other people from using them. Coca-Cola, for example, is a trademark of the Coca-Cola Company -- if I start selling my own drink and calling it 'Coca-Cola', or even something like 'Cocoa-Cooler', then they have grounds to sue me.
Making Your Mark.
You can trademark both your business' name as well as the names of any products you sell. The only condition is that they can't be too similar to names that someone has already trademarked, and you can't usually trademark words that are in common use.
It costs a few hundred dollars to register a trademark, and you can do it through the patent office. It can be a waste of money to trademark too many words, so you should only bother with it if you think one of your names could be threatened by competitors.
Once you get your trademark, it's yours -- you can do whatever you want with it, including giving others permission to use it or selling it to them. Remember, though, that your trademark usually only applies in the country where you registered it -- you will not usually be protected from competition where foreign businesses are using your trademark. Also, your right to use the trademark will only last for a set number of years (usually a decade from the date of registration). After this time, you will have to pay again to renew it.
Don't Copy Me.
Copyrights are similar to trademarks in terms of the kind of protection they offer, but different in how they work. In almost all countries, ownership of copyright is automatic, and costs nothing. The moment you write (or draw, or record) something, you own the copyright on it, and can take action against anyone who makes a copy of it without your permission. This article you're reading right now, for example, has the automatic copyright. If you decided to copy it without permission and put it on your own website, then that would be illegal. Not that you would do such a thing, of course.
It is possible to own the copyright on almost anything that exists but isn't physical: music, graphics, writing, computer programs, and so on. It does not, however, cover physical things (that's patents), nor does it cover names (that's trademarks).
A copyright lasts longer than a trademark: typically it lasts until you die, and then a set number of years after that, depending on your country and the kind of thing that was copyrighted. After the end of this time, the work becomes 'public domain', free for anyone to use.
Of course, copyright is a right, not something that you absolutely must go along with. If you want to give people permission to freely use and redistribute something you've made, then you have the legal right to do this. You can even give up your copyright on a piece of work altogether, simply by writing on it that you no longer want to own the copyright.
Since you're in business, though, the chances are that you'll want more protection for your materials, not less. Look into registering your copyright at the patent office, as doing this will give you an even stronger case if you ever need to use it.