If you are expecting a refund you can check the IRS website, Where's My Refund? 28 days after mailing your tax return.
If you are not expecting a refund tracking you can use the IRS new online transcript request option to tell when your return has been processed. Once the return shows up in the transcript request the IRS has received and processed your return. Before that time it will show that you have not filed for the year. You can also determine when the IRS processes your payment (if a tax payment was sent/due) by clicking this link: http://www.irs.gov/Individuals/Get-Transcript
After 21 days have passed you may also call the IRS customer service at 1-800-829-1040 to inquire the status of your tax return.
