This website has a lot of links to a lot of different topics, not just government. Students can choose government under the specific grade ranges (K-5 or 6-8) and gain access to links to the various parts of government. This would be a great resource for students to start their research.

This is website is broken down into various age levels. Each level has information appropriate to that grade. There are also links to sites for kids with more information on the different topics.

This site contains a lot of great information about the various U.S. symbols. There are sites with information as well as sites with printouts. This is a great site for teachers and students.