The U.S. Internal Revenue Service said today it’s mailing educational letters to 650,000 tax-exempt organizations informing them of new filing regulations. The intent of is to notify tax-exempt organizations that a new form, form 990-N, or an “e-Postcard,” will be required beginning in 2008. Before the new regulations, tax-exempt organizations with gross receipts of $25,000 or less were not required to submit information returns.