The New York Times is reporting that Sonia Sotomayor is President Obama's choice to replace Justice David Souter on the Supreme Court. For a comprehensive review of Sotomayor's work, I would recommend going over to SCOTUSBlog, where her opinions are discussed here, here, here, here, and here. Sotomayor, who is of Puerto Rican descent and grew up in the Bronx, would be the first Latino justice on the Supreme Court. For SCOTUSBlog's view on the likely lines of attack against Sotomayor, read here.
UPDATE: Uh, judging by some of the coverage of the Sotomayor announcement, there are a number of reporters who don't have a very well developed knowledge of geography. Puerto Rico is part of the United States, and Puerto Ricans are Americans by birth. I'm unsure of when Sotomayor's parents were born, but unless they moved to the Bronx before the Jones-Shafroth Act of 1919, then they were Americans, not "immigrants."
-- A. Serwer