August 2 is the deadline for employers to file quarterly Form 941 for income, Medicare, and social security taxes withheld from their employees' salaries in April, May and June. If the tax for the quarter has been deposited in full and on time, employers have until Tuesday, August 10, to file the return.

Before you mail any check to the Internal Revenue Service, be sure to complete the following: 

• Note the reason for the payment, the form number and the year of the return for which the check is being sent. For example, "balance due on Form 1040 for 2008."
• Include your social security number or your employer identification number if you operate as a business.
• Make all checks payable to the U.S. Treasury.