Naval-History.net: A splendid resource for naval history, with many useful sources, including a collection of Royal Navy log books from the First World War.
Naval Historical Centre, the official website of the US Navy and an excellent resource for all American naval history. Especially impressive is the Dictionary of American Naval Fighting Ships, with over ten thousand entries!
HFM Pyrotechnics: The company who provided the 52-gun salute fired by HMS Victory during the Trafalgar 2000 celebrations
My Navy Story - memories of time spent on USS Mississippi, written by Louis E. Van Slyke, Chief Machinists’ Mate, USN
Rusnavy.com: The largest English-language Internet site on the Russian Navy