If you are planning to start a business or are a startup that has not yet incorporated, you will need to register with your Secretary of State. Before doing that you will need a corporation name - use the links below to search in your state and ensure that the name you want is not taken.
Secretary of State offices will most often not reserve a name that is not legally registered, so after verifying that the name is not taken in your state you will want to file immediately through an appropriate legal services group (be it your lawyers or an online service like LegalZoom).
Other corporate branding considerations
Domain name: Ideally you will want your domain name to match your company name. Domain Name Registrars such as GoDaddy can perform a search and register your domain name.
Logo: A visual mark to represent your company is very important. You can find artists on sites such as CrowdSpring or 99Designs.
Dunn & Bradstreet number: This serves as a sort of credit rating service - by securing your number you will be able to see how your company is rated the same way a potential lender or service provider will. See Dunn & Bradstreet Credibility Corporation's site for more.
Click your state to open your state's Secretary of State page