Support for printing will in fact be coming in version 0.5. I’ve committed (to my branch) a new printing framework that fixes the bugs in the old one. Also, I’ve committed some PDF changes. There is now an any2pdf app which will allow for conversion of any supported ebook format into the PDF format. PDF files will also have the first page used as the cover image within Calibre’s library.
If you want a perfect printed representation of an ebook as it is viewed in the ebook-viewer application use any2pdf to convert the ebook into a PDF file.
Just like with the last implementation for printing this could change at some point. However, this version has been deemed good enough for inclusion.