Wikipedia (I don't think she maintains her own website) and find her work on Amazon.
I chose to list Alice B. Sheldon here under her famous pseudonym of James Tiptree Jr. She was a native Chicagoan, a major in the Army Air Forces during World War II, and a woman with "a complex sexual orientation." Her novel Brightness Falls from the Air was another book that kept me reading way past my bedtime; however, I need to read some of her short stories too. Unfortunately, it doesn't look as if her work has been converted into eBook yet. I hope it is so she can find a new generation of readers. The Tiptree Award is named after her, and several of the authors I've already listed have won it. Learn more about her on Wikipedia and find her stories on Amazon.
Honorable Mention: Amy Thomson, author of Virtual Girl, The Color of Distance, and Through Alien Eyes. Links to Wikipedia and Amazon.
Feel free to list more terrific T women SF authors in the comments.