I own a small business and was told that changing my business into an S Corporation is a good idea. Can someone please explain what an S Corporation is and why it's good idea for small business owner.

The best source of this information is your tax attorney or accountant. But the gist of it is that the S corporation enjoys favorable tax treatment. Its earnings are taxed only once. The standard corporation's earnings are taxed when earned by the corporation and again in the form of dividends to owners.