Metz lies along the A31, north of Nancy and south of Luxembourg. From Paris or Strasbourg, take the A4 to the A31; Metz is just to the south.
There is a small regional airport for Metz and Nancy code: ETZ, located southeast of Metz. This mainly handles commercial traffic, but there are passenger flights to/from Paris, Lyon, Algiers, and several Italian destinations.
A shuttle bus (http://www.flibco.com/hah...) is also available from Frankfurt-Hahn airport.
Metz is also reachable by train including TGV, with connections to/from Paris, Luxembourg, and Strasbourg. The train station is at the southern edge of the city center. You should note that if you have a eurail pass you will probably not be able to leave for a few weeks you must make reservations way in advance.
