I recently found out that I did not include some of my income on my tax return. What should I do?

Answer:
You must file an amended tax return: IRS Form 1040X. According to the instructions for Form 1040X, your amended return must be filed within three years after the date you filed your original tax return, or two years after the date you paid your taxes for that year, whichever is later. If you filed your return before the due date, it is considered to have been filed on the due date. For instance, if you filed your 2010 tax return on January 1, 2010, it is considered to have been filed on April 15, 2010, and the three-year period starts April 15, 2010. On the form, be sure to indicate the year of your original return, and include any required attachments and explanations of your reasons for filing an amended return.