I'm having the same problem. (Has there really been no answer here for 3-4 months?). The Fact sheets from the Census Burea's site say to download the ArcGIS Explorer free and give instructions for joining censis data to the Tiger Line shapefiles (and I really only need to join a few columns). The instructions look entirely different than the current interface. I guess that's understandable, because they're for 9.x and it seems we're now on 10.x, but there simply seems to be no way to join data to a shapefile on standard census numbering (for tracts, county subdividions, places, etc.) The only options I see for joining text data and shapefiles is based on street addresses, military geocoding, or longitude/latitude. Seems very strange, as a text join is pretty basic. And I'm really confused that the Census would provide a link to download a program that does not allow the very functions their instructions envision. Am I missing something? Please help.