Originally Posted by coredump
And books that I buy on other places that have DRM? Like the ones at baen books.
Baen books are DRM-free. They have ePub and LRF versions, both of which will work on the Sony.
For DRM-ridden ebooks, it might be possible to download Adobe PDF and ePub ebooks by using Windows Adobe Digital Editions under wine. You would need to authorize your Sony Reader to your AdobeID account one time on a Windows PC.
The alternative is to buy DRMed eReader or MOBI ebooks, both of which work from any web browser, strip their DRM and convert to LRF or ePub using Calibre. For MOBI you would need to provide a PID from a device supporting MOBI DRM. The easiest is probably a Windows PC running MobiPocket Reader. You just need the PID (a 10 character identifier), then everything else works under Linux.