Oh in case it is history you're interested in, I'm going to "dump" one more link in here before I forget ...
"Habsburg" is an academic "discussion network" (read: mailinglist) of high quality, which deals not just with Habsburg times, but also the subsequent history of the various successor states. Very good book reviews, in particular.
Dagmar is right though, of course - we should have waited until you told us more about what you're interested in before we started pelting you with links ... nowadays sorting through the links is the trick, rather than just finding them ...