From the new EBL blog:
Sony Reader and Adobe announced the release of Digital Editions firmware which can be loaded onto the Sony Reader PR505 and the new PR700. As EBL download uses Adobe Digital Editions, EBL ebooks can now be loaded onto Sony Reader devices.
You can read more about the software and how to get it to work on the Sony Reader hereâ€¦
EBL is one of the only major ebook providers which enables downloading to Adobe Digital Editions and so is among the first to be able to offer downloads to reader devices!