Ada Lovelace

The only legitimate child of Lord Byron, a well known Romantic poet most of us know from our AP English classes, Ada Lovelace was encouraged to study mathematics and science by her mother who feared that she would otherwise end up a poet like her father.
Lord Byron called her "The Princess of Parallelograms". Ada was introduced to Charles Babbage by Mary Somerville, her teacher and a noted scientific author.
Ada wrote a program for Babbage's proposed Analytical Engine. Had the machine actually been built, her program could have calculated the Bernoulli number sequence. This is why Lovelace is popularly identified as the first computer programmer.
Impressed by her talent, Babbage called Ada "The Enchantress of Numbers". Forget this world and all its troubles and if possible its multitudinous Charlatans - every thing in short but the Enchantress of Numbers.
Was Ada the first ever computer programmer? Ada suggested and described several computer programs to concrete the idea of the Analytical engine, but hardly wrote them on her own. Nonetheless, without her beautiful prose, the Analytical engine would have remained in undocumented obscurity.
The programming language Ada, developed by the U.S. Department of Defense, was named in her honor.

A portrait of Ada Lovelace
Grace Hopper
Grace Hopper was a computer scientist with the U.S. navy. She was one of the first programmers of the Harvard Mark I calculator. Called 'Amazing Grace', Grace Hopper developed the first compiler for a computer programming language.
Grace was the first to receive the "Man of the Year" award from the Data Processing Management Association. She was the first woman of any nationality to be made a Distinguished Fellow of the British Computer Society.
Women employees at Microsoft formed an employee group called "Hoppers" in her honor that awards scholarships to promising candidates.
Edith Clarke

Image Source: [http://women.cs.cmu.edu]
A mathematics student from Vassar College, Edith Clarke was the first female electrical engineer in the U.S. She was also the first woman to get an M.S. degree in electrical engineering from MIT.
Edith invented the Clarke calculator, a simple graphical device that solved line equations involving hyperbolic functions ten times faster than previous methods.
Being the first woman to deliver a paper at the American Institute of Electrical Engineers' annual meeting, Edith Clarke showed the use of hyperbolic functions for calculating the maximum power that a line could carry without instability.
Adele Goldstine

Team of workers with the ENIAC - Adele Goldstine on the extreme right
Image Source: Computer Desktop Encyclopaedia
A pioneer in the field of operating systems, Adele wrote the complete technical description for the first digital computer, ENIAC.
Beginning in the fall of 1942 at the Moore School, Adele Goldstine began training women to calculate firing and bombing tables, using mechanical desk calculators. Known as "computers," the women selected for the program ultimately could perform the complex series of mathematical calculations in about one or two days.
Along with Jean Bartik, she led a group that implemented John von Neumman's "stored program" computer. This solved the problem of the programmers having to reconfigure all of the cables for each equation that the machine solved.