You do not have too many options If the size of pages in pdf is much bigger that the size of Sony reader screen.
1. You can split each page by
JAP (Just Another Printer) program and read it piece by piece
2. You can make the script more solid by
PDFRasterfarian
3. You can extract text and all pictures by
ABBY PDF Transformer and transform it into another format.
I prefer the third way. Pdf -> Rtf -> Lrf. I use
Book Designer 
to make Lrf from Rtf. The result is