Don't think that there is anything off the shelf at the moment but for consideration:-
1) First method - you must have a working internet connection through your phone, a Gmail account & web browsing application (opera mini or bolt browser) email your (named).pdf file to your email address (as a attachment). Then sign in to your gmail account through a web browser. Then read your new email. At the end of the page there is View : basic HTML > Select it. > Open attached pdf file
2) Secondly there was an application Zesium Mobile .pdf suitable for S40, but think developer has moved on and no longer sells activation licenses.