Middle Class Jobs Protection Act of 2008 - Amends the Internal Revenue Code to: (1) reduce the maximum corporate income tax rate to 25%; (2) increase the expensing allowance for depreciable business assets to $250,000 in 2008 and 2009; (3) increase to 50% the current year bonus depreciation allowance for certain property placed in service in 2008 and 2009; and (4) allow additional carrybacks for certain net operating losses and for excess business and foreign tax credit amounts arising in 2008 and 2009.