An LLC is a disregarded entity for Tax purposes. You may want to look a little deeper into potential US corporate structures before choosing the one that is right for you...
A LLC can choose to be considered a sole proprietorship/partnership (depending on the # of owners) or a corporation. The tax liabilities will be different. If it is a sole proprietorship/partnership then the tax liability for the LLC is 0% (because it is directly on the owners) and if it chooses to be a corporate it will pay taxes as such, I don't know the exact %. I ran a search in Google with the key words LLC Tax Liability and got 87,000 hits so I am sure you can find a lot of material there... From www.irs.gov : For IRS purposes, how do I classify a limited liability company? Is it a sole proprietorship, partnership or a corporation? A limited liability company (LLC) is an entity formed under state law by filing articles of organization as an LLC. Unlike a partnership, none of the members of an LLC are personally liable for its debts. An LLC may be classified for Federal income tax purposes as a sole proprietorship (referred to as an entity to be disregarded as separate from its owner), partnership or a corporation. If the LLC has only one owner, it will automatically be considered to be a sole proprietorship (referred to as an entity to be disregarded as separate from its owner), unless an election is made to be treated as a corporation. If the LLC has two or more owners, it will automatically be considered to be a partnership unless an election is made to be treated as a corporation. If the LLC does not elect its classification, a default classification of partnership (multi-member LLC) or sole proprietorship (single member LLC) will apply. The election referred to is made using the Form 8832 (PDF), Entity Classification ElectionIf a taxpayer does not file Form 8832 (PDF) , a default classification will apply.