http://www.uhrp.org/
A group with a human rights focus on the Uyghurs. This group of people are NOT Chinese by any stretch of the imagination, and this repression is a racist, genocidal effort by the dictatorship that rules the People's Republic of China.
Here is Amnesty's page for protesting the treatment of Rebiya Kadeer, an Uighur prisoner of conscience. They recommend a letter for her release to
His Excellency Ambassador Yang Jiechi
Embassy of the People's Republic of China
2300 Connecticut Avenue N.W.
Washington, D.C. 20008
fax: (202) 328-2582
I suggest that we write for Mr. Sitiwaldi (Dilkex) Tilivaldi, too.