rmm20, that is not correct. Sony eBooks WILL work on the nook.
Both B&N and Sony use the Adobe RMSDK. B&N added to it their new DRM, but the old DRM which the sony uses still works. So yes, any books you buy from the sony store CAN be used on your nook. If you bought them a while ago you may need to re-download them to make sure you have the ePub version of your books and not the lrf version.
Please check out the following link to read about reading books from Sony or Overdrive on your nook:
http://blog.threepress.org/2009/12/1...nderer-review/