The goal of this link collection is to give a brief overview of web pages that might be of help in getting your own researches started. This choice is certainly incomplete and a result of subjective preferences.
You can find more complete genealogical link collections in directories like Cyndi's List or Biggis List and on the pages of various genealogical societies.
The most important sources for your research are primary sources. The pages of the Polish State Archives give a perfect overview of existing archives and their holdings. The online database PRADZIAD informs about available vital records.
The Archives of Plock and Torun along with their branches have their own pages.
The sources that have been filmed by the LDS - Church of Jesus Christ of Latter-day Saints are searchable in their database using the LDS Filmsearch pages. An annotation because of a frequently asked question: It is a catalog of the microfilmes that can be viewed at one of the LDS Family History Centers, not a direct access to digital church book pages.
The German Bundesarchiv keeps historic German state records and makes them publicly available. They still have the filmed records of the Polish areas occupied in 1939 (the original records have been handed over to the Warsaw Archive of New Records).
The Department of Cartography and Geoinformatics of Eötvös Loránd University, Budapest, Hungaria offers 267 sheets of the Map of Central Europe as of 1910 (scale 1:200 000) for download.
An interesting map can be downloaded from the ambitious Digital Library of the University of Łódź. The Special Karte von Süedpreussen by David Gilly might be of genealogical interest. This map was published 1802-1803. But it shows the borders of South Prussia before the Third Partition of Poland.
New views on old maps - a project of the State and University Library of Bremen, Germany enables the online access to historical maps. The patient visitor is rewarded by some maps of the area of Central Poland.
The Fotogaleria miasta Płocka offers a huge number of interesting photos showing the city of Plock and surrounding areas. Aerial photographs demonstrate the process of the construction of the new bridge. Parts of old maps and detailed satellite pictures allow a great overview and an interesting comparison.
Older Roman-Catholic church records are written in Latin language. A valuable helper for these is provided by the Catholic University of Notre Dame (Indiana, US) in form of the Latin Dictionary and Grammar Aid.