Although you should always consult with a professional to learn all the consequences of incorporating, many small business owners choose to form an S corporation to save money on self-employment taxes. This can save thousands of dollars a year for small business owners.
For example, although you'll still have to pay yourself a reasonable salary, any amount above and beyond that can be paid out to you as the shareholder, tax free. So, if your business earns $95,000.00 in a given year, and a reasonable salary in your line of work is $65,000.00, you just saved paying taxes on $30,000.00.
On the downside, there are many forms and some record keeping that you'll have to stay on top of if you choose to form an S corp. You can read more about this process and the pros and cons at TheMoneyAlert.com.