Hi,
Our friends from "Project:Poland" have created such a monuments search engine:
http://wikilubizabytki.centrumcyfrowe.pl/
It does generally 3 things: a) in the first field you can put a keyword for a name of monument - b) in the second field you can put the name of the place - i.e. a name of the village, county, city district etc. c) in the third field you can put the number or part of the number of the monument and see its offical name and address
For example: if you put in the first field the keyword "pałac" (palace) you will get a list of all palaces in Poland which have official heritage status. If you add to the second field the keyword "Warszawa" - you have a list of all palaces in Warsaw.
Cheers,