I just remembered a little gem that was mentioned some time back, don't remember who's idea it was, or I'd give them direct credit. So anyway, just know I'm not claiming it as
my idea.
If you have or set up a
gmail account you can e-mail yourself your PDF files and your gmail box will let you view them as HTML, with all the italics, bolding and such more or less intact. From there, converting it for the Reader is trivial, HTML2LRF has already been mentioned, saving the thing as an HTML file and then converting to RTF with Word or Open Office is no challenge. And popping it into the also aforementioned BookDesigner is also a simple matter.
I expect there might be some reformatting needed with this method, but it should be a lot less than otherwise.
I had forgotten about it, since I don't use PDFs much myself.