To download the installer for Sony’s Reader Library software update that now includes the PRS-350 Pocket Edition and PRS-650 Touch Edition, hit this page. [Fixed link. Select your OS. Unfixed link was for Windows only!]
Sony Reader PRS-350 Pocket Edition User Guide link is on this page.
Sony Reader PRS-650 Pocket Edition User Guide link is on this page.
Sony Reader PRS-950 Daily Edition User Guide is not yet available.