U.S. Switches to a First-to-File System
The Leahy-Smith America Invents Act that was signed into law in 2011, goes into effect on March 16, 2013. Representing the most significant changes to U.S. patent law since the 1950s, the new act will see the current first-to-invent system changed to a first-to-file system.
Diana Cooper, LW student-at-law, goes into more detail in a recent blog post.