Of late, we have attended some meetings discussing community involvement and redistricting. To get up to speed, we created some boundary GIS layers of state-level congressional districts and tacked-on some ethnicity and population attributes.
These layers are available for free at ArcGIS online. If you use arcmap, click on the add data link and navigate to ArcGIS online. Search redistricting and scroll through the cool stuff until you see usc_public layers.
Otherwise, download arcexplorer or run arcviewer online. Then, add content and search redistricting