Calibre has a fine collection of newpapers and magazines available for download.
I downloaded today's "The Irish Times" via Calibre, saved it as an .lrf disk file, then imported the .lrf file into the Sony eBook Library. I then uploaded the file from the eBook Library onto the 505. Downloading the paper into Calibre took a couple of minutes; the remaining operations were no more than a minutes work.
I was surprised how well Calibre formatted the newspaper on the PRS 505. All the various sections were easily accessible, and within each the various articles, columns and even letter to the Editor.
Excellent job Kovid