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.
Happy to have helped forum with a Support Ratio = 42.5