Employees may use this form to determine whether or not they can claim additional moving expense deductions when filing their income tax return. Form 3903  summarizes the total cost for transportation, storage, and lodging minus the amount reimbursed from the employer. This amount may be used as an additional income tax deduction. To determine whether or not they can claim an additional moving expense deduction, the employee should contact the Internal Revenue Service or their tax advisor.
See http://www.irs.gov/pub/irs-pdf/fw9.pdf  for more information.