These are links to Federal level websites involving taxes.

• Internal Revenue Service
  General: (800) 829-1040
  Refund: (800) 829-4477
  
• Social Security Administration
• Medicare

State-level Website Resources

• Arizona Dept of Revenue
  General: (602) 255-3381
  Businesses: (602)255-2060
  
• AZ Dept of Economic Security (AZ Unemployment)
  
• All States - Depts of Revenue

Selected Arizona County Websites

• Real Estate Property Tax:
  Maricopa County Treasurer
  Pinal County Treasurer
  Pima County Treasurer
  

Other Links of General Interest

• Federal Trade Commission
  Credit Laws and "No Call Lists"
• Non Profit Organizations
• Free Credit Report
• New & Used Auto Prices
• Historical Stock Prices
• Currency Exchange Rates
• E-Court Programs through Maricopa County
  

Handy List of Online Calculators for Common Accounting Tasks

• Compound interest
• Mortgage calculator
• Retirement calculator
• 401(k) Calculator