21st Century Teacher Training Act of 1999

21st Century Teacher Training Act of 1999 - Authorizes the Secretary of Education, through the Office of Educational Technology, to award competitive grants to local educational agencies (LEAs) to provide intensive classroom-related computer training for teachers.

Requires grantees to enter into contracts with institutions of higher education or other nonprofit educational providers under which the contractor will establish, operate, and provide the non-Federal share of the cost of such teacher training programs.

Requires such teacher training programs to: (1) be conducted during the school year and during the summer months; (2) train teachers who teach grades kindergarten through college; (3) select teachers to become members of a teacher network whose members will conduct workshops for other teachers employed by the LEA; and (4) encourage teachers from all disciplines to participate.

Amends the Internal Revenue Code to establish a personal income tax credit of up to $1,000 for technology-related professional development expenses for eligible teachers.

Provides such credit for qualified technology expenses which: (1) would be allowed as a deduction for being related to teaching activities (but prohibits a double benefit of both deduction and credit for the same expense); and (2) are for training in the use of technology in the classroom. Includes among such expenses the cost of any computer or technology equipment that is used at least 50 percent for teaching-related activities.

Expands the deduction for computer donations to include donations to public libraries, as well as to schools.

Establishes a business-related tax credit for donations of computers to schools and public libraries.