Here’s the setup. O’Reilly hosts a django based open source ebook reading website called bookworm.  You can run bookworm on your own server.  I opened a ticket on bookworm’s bugtracker to provide an api method to update where you are in a book.  Next you update Aldiko (Not open source, but perhaps we can write a plugin for it) and FbreaderJ to use that method when they exit to update where you stopped reading.
Upshot: You open a book on your phone and read it. Â It syncs with your server with a bookmark of where you stopped reading. Â Then you go to your website, and begin reading from where you left off. Â And so on. Perhaps your phone also detects when it gets a new ebook and uploads that to your server or downloads a new book from your server when one shows up as well.
But wait, there's more
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It's been done. It's called Kindle.
Huh, I've never heard of this thing before. Is it backed by some huge company with tons of resources? They will never stop being interested in providing me this service.
By the way, did you see this thing I wrote?
http://www.morelightmorelight.com/2011/08/30/micr… So weird, it seems microsoft had an ebook reader and when they stopped making enough money on it they discontinued the DRM servers and now if you have any of their ebooks they are worthless.