Any business with employees will need to pay unemployment insurance taxes, report new hires, and comply with other filing and reporting requirements. Make sure you fullly understand your obligations as an employer before you hire your first employee. If you are required to pay unemployment insurance taxes, you will need to register with your states's workforce tax agency.
Below are links to each state agency that handles business employment matters, including unemployment insurance tax, employee reporting requirements, and other employee-related matters.
To find other state-specific as well as federal resources, see Nolo's Small Business Resources section.