H.R.3907 - Federal Government - To amend the Internal Revenue Code of 1986 to provide tax relief for small businesses.

Small Business Tax Relief Act of 2007 - Amends the Internal Revenue Code to: (1) make permanent the work opportunity tax credit, the new markets tax credit, and the tax credit for increasing research activities; (2) make permanent accelerated depreciation of qualified leasehold improvement and restaurant property and expensing of environmental remediation expenditures; (3) increase the partial tax exclusion of gain from sales of certain small business stock for noncorporate business taxpayers and businesses in an empowerment zone; (4) permit certain small businesses to elect taxable years ending between April and November; (5) increase the allowable number of S corporation shareholders from 100 to 150; and (6) exempt certain small businesses from the 3% withholding requirement applicable to payments made to such businesses by government entities.