Some sites I found useful when travel to Czech Republic.

Czech Republic:

Prague:

Prague Experience - hotel and apartments rentals;
Prague Hotels Guide - hotel and apartments rentals,
(Stayed at U Karlova Mostu);
Prague City Travel Guide - historic info and sightseeing;
Prague Information Service;
Radio Prague's History OnLine - historic info;
Maps of Prague;
Interactive map of Prague.

Some books I found useful when travel to Czech Republic (from amazon.com).