The Internal Revenue Service is looking for 4,200 Georgia taxpayers who are due refund checks worth more than $5 million. The checks were returned to the IRS by the U.S. Postal Service due to mailing address errors..Taxpayers can find out if they are due a tax refund by visiting the IRS Web site at http://www.irs.gov and clicking on ‘Where’s My Refund.’ To use this feature, enter information from the 2008 tax return including the Social Security number, filing status and refund amount. Taxpayers will get the status of their refund check and in some cases also get instructions to resolve potential account problems.Taxpayers can also check on the status of the refund by calling 1-800-829-1954. Taxpayers checking on a refund by phone will be given instructions on how to update their address.