IFilm.com has put three scenes from Nemesis online. The scenes include Jean-Luc Picard and his crew being introduced to the new Romulan Praetor Shinzon, a pulse-pounding battle between the U.S.S. Enterprise-E and Shinzon's flagship the Scimitar and a dramatic confrontation between Picard and Shinzon toward the end of the film. Below are some images from the movie.
The scenes can be found here at IFilm.com. Thanks goes out to Venture.
Source: StarTrek.com