Small Business Expansion and Job Creation Act of 2010 - Amends the Internal Revenue Code to extend through 2010: (1) the increased ($250,000) expensing allowance for depreciable business assets; (2) the additional 50% depreciation allowance for certain types of investment property acquired in 2010; and (3) the election to accelerate the tax credits for the alternative minimum tax and research expenditures in lieu of bonus depreciation.