landscape mode is available with the Aldiko ereader, but only under an 'enabled' Nook Touch (not too hard to do using a computer, SDHC microsd carrier, and a few simple command-line incantations)
that said, i like the flexibility of being able to change orientation - comes in handy once in a while...
the ability to flip screen orientation has been around for quite some time - used to use it on my Zaurus 5500, and currently supported by fbreader on my Nokia N800
alternatively, how about recasting the pdf (e.g., rotating the pages), saving the file, and then reading on your nook?
Last edited by linux_author; 07-22-2011 at 02:09 PM.