mixing character sets

I have been asked to do a proposal for pretty simple CMS tool that will need to handle multiple character sets including Kanji. of course we are using PHP and the client has Oracle. >From what I understand the administration pieces will be in English but will display other language content. As I have never done something with this requirement I am a little nervous about what I am undertaking. Beyond selecting database field types that will handle the range of character types, is there anything else we should be considering when starting to budget and design our PHP/DB application? Has anyone scene any resources on the web for building multi-lingual PHP apps? Thanks -Paul