Incentive to Serve Tax Act - Amends the Internal Revenue Code to allow employers a business tax credit for 25% of wages paid to employees while such employees are performing certain services (e.g., services advancing the improvement of education, health care access, energy conservation, economic opportunities for economically disadvantaged individuals, and disaster preparedness and response) for charitable organizations and community agencies. Limits the amount of wages eligible for such credit to $100,000 per employee.