U S City Directories at Ancestry.com
Ancestry.com says it is new, but I'm not certain how new the U. S. City Directory collection actually is. The search may have been changed or a few cities/locations might have been added. An admittedly quick scan of the locations and places included seemed to indicate that this database is the directories that were uploaded several years ago in an attempt to make up for the lack of the 1890 census.
The city directories can be searched here.
I would be interested to see if others think this is the same set of data that was already on Ancestry.com.