Recommend an IRS site? Sure, if it's a good one. And this is. Here is what the IRS labels a Small Business and Self-Employed One-Stop Resource. If you're looking for a place to investigate and gather information on the nuts-n-bolts of starting a small business, they're not far off.
If you're considering starting a business, start here. This section provides information such as a checklist for a new business and selecting a business structure. Learn about operating a business with employees, deductions and credits, recordkeeping and Accounting methods. Additional resources include the Small Business Tax Calendar, Tax Topics for Businesses, and Frequently Asked Questions.