Witness Security and Protection Grant Program Act of 2010 - Directs the Attorney General to: (1) make competitive grants to state, tribal, and local governments to establish or maintain programs to protect or assist witnesses in court proceedings involving homicide, a serious felony or drug offense, or gangs or organized crime; (2) evaluate grant applicants based on specified criteria, including such government's level of witness intimidation and level of serious crimes; (3) provide technical assistance to grant applicants for establishing or maintaining a witness protection plan; and (4) develop and disseminate within one year after development best practice models to assist states and other relevant entities in addressing witness safety, short-term and permanent witness relocation, financial and housing assistance, and other necessary services.

Expresses the sense of Congress that states and relevant entities should use the best practice models developed by the Attorney General to evaluate, improve, and develop witness protection or witness assistance programs.

Requires the Attorney General to: (1) ensure that grants funds under this Act are equitably distributed throughout the United States and that due consideration is given to applicants of rural and urban communities; and (2) report to Congress not later than December 31, 2012, on the implementation of this Act and not later than December 31, 2015, on the programs funded by grants awarded by this Act.

(This measure has not been amended since it was reported to the House on June 8, 2009. The summary of that version is repeated here.)

Witness Security and Protection Grant Program Act of 2009 - Directs the Attorney General to: (1) make competitive grants to states, tribal, and local governments to establish or maintain programs to protect or assist witnesses in court proceedings involving homicide, a serious felony, or a serious drug offense; (2) give priority to grant applications for programs in states with an average of not less than 100 murders per year during the most recent five-year period; (3) provide technical assistance to grant applicants for establishing or maintaining a witness protection program; (4) develop best practice models to assist states and other relevant entities in addressing witness safety, short-term and permanent witness relocation, financial and housing assistance, and other necessary services and disseminate such models to such states and entities within one year after their development; and (5) report to Congress on the grant programs and the development of best practice models not later than December 31, 2015.

Defines states, for purposes of this Act, as any state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, America Samoa, Guam, and the Commonwealth of the Northern Mariana Islands.

Expresses the sense of Congress that states and relevant entities should use the best practice models developed by the Attorney General to evaluate, improve, and develop witness protection or witness assistance programs.

Provides that nothing in this Act requires the dissemination of any information if the Attorney General determines that such information is law enforcement sensitive or poses a threat to national security.

Authorizes appropriations for FY2010-FY2014.

Witness Security and Protection Grant Program Act of 2009 - Directs the Attorney General to: (1) make competitive grants to states, tribal, and local governments to establish or maintain programs to protect or assist witnesses in court proceedings involving homicide, a serious felony, or a serious drug offense; (2) give priority to grant applications for programs in states with an average of not less than 100 murders per year during the most recent five-year period; (3) provide technical assistance to grant applicants for establishing or maintaining a witness protection program; (4) develop best practice models to assist states and other relevant entities in addressing witness safety, short-term and permanent witness relocation, financial and housing assistance, and other necessary services and disseminate such models to such states and entities within one year after their development; and (5) report to Congress on the grant programs and the development of best practice models not later than December 31, 2015.

Defines states, for purposes of this Act, as any state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, America Samoa, Guam, and the Commonwealth of the Northern Mariana Islands.

Expresses the sense of Congress that states and relevant entities should use the best practice models developed by the Attorney General to evaluate, improve, and develop witness protection or witness assistance programs.

Provides that nothing in this Act requires the dissemination of any information if the Attorney General determines that such information is law enforcement sensitive or poses a threat to national security.

Authorizes appropriations for FY2010-FY2014.

Witness Security and Protection Grant Program Act of 2009 - Directs the Attorney General to make competitive grants to state, tribal, and local prosecutors to establish or maintain programs to protect or provide assistance to witnesses in cases involving homicide, a serious or violent felony, or a serious drug offense.

Directs: (1) the U.S. Marshals Service to provide technical assistance to recipients of grants under this Act; (2) such recipients to submit reports to the Attorney General evaluating witness protection programs; and (3) the Attorney General to develop best practice models to assists states and other entities in addressing witness safety, witness relocation, financial and housing assistance for witnesses, and other necessary assistance.