You should perform a multiple check on a proposed corporate name by following these three steps:
Once you're sure the name you want for your corporation is available, you can reserve it in most states so it will be available when you are ready to incorporate. Read Reserving a Corporate Name for more information.
Get detailed information on this and other considerations for your startup business by reviewing the AllBusiness.com Step-by-Step Guide to Incorporating a Business.
In addition, make sure to read these articles: