If you are planning on forming an LLC corporation, the only thing that you will need to do differently is file a Form 8832 with the IRS. The reason you need to file this form when forming an LLC is because it allows you to classify your business for federal tax purposes. In certain cases, you do not need to file this form because your business will automatically be classified as that way. This can happen because of the entity classification rules that are set forth by the IRS. If you plan on forming an entity that fits into one of the guidelines set forth by the IRS than you will not have a choice as to how your LLC is going to be classified for federal tax purposes.
Any limited liability company that is formed under a federal or state statute or under a statute of a federally recognized Indian tribe is automatically classified as a corporation if the business entity describes or refers to itself as incorporated or a corporation. Your business will also be classified as a corp for federal tax purposes if it is formed under a federal or state statute that describes or refers to the company as a joint stock association.
Many people who are forming an LLC do not wish to file it as a corporation because of the tax consequences that they face. If you want to be safe, you should consult with a CPA or tax attorney to get some legal, certified advice before filing an entity.