Several Hungarian directories are full-text and soundex searchable at
genealogyindexer.org, including an enormous 1931 business directory, a
1940 industry directory, and a 1943 telephone directory, all covering
the entire country. To search, go to genealogyindexer.org, type your
search term (e.g., surname) in the search box, change the "Any Place"
option below the search box to "Hungary," and press the "Search"
button. Search results link to scans of the matching directory pages.
Some of the directories are organized by town, and, if you are a town
leader, you could extract all the entries for your town and put them
on your town's website (to find your town in the 1931 business
directory, see http://genealogyindexer.org/forum/viewtopic.php?t=5035).

Others have mentioned searchable Budapest telephone directories
available elsewhere. If you know of Hungarian directories that you
think I should add to genealogyindexer.org, please contact me.

Logan Kleinwaks
kleinwaks@alumni.princeton.edu
near Washington, D.C.