A good internet site is ship-technology.com and naval-technology.com... But its not as thorough as I would prefer.
(warning, rumour)
The *-technology.com site network supposedly simply collects its data from other sources including Jane's (and imo if they do that, they're doing a relatively good job at it) and a variety of online publications.
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There's a dual-language German/English publication, "Weyers Flottentaschenbuch - Warships of the World / Fleet Handbook".
Enjoy's a similar good fame as Jane's naval publications or Combat Fleets of the World, however it's considerably cheaper - €64 for the current 2005-2007 edition. Appears every three years or so, so not as up-to-date necessarily. Current edition might be a bit hard to find though, Amazon outside Germany and such don't carry it of course.
Old editions (60s in particular, for those interested in those times!) are available from $10 upwards on Amazon, the 80s and 90s editions already run from $25 upwards used.
Well, and for those that read German and have an interest in naval matters,
DMKN is pretty much a must.