Converting PHP/mySQL sites into UTF-8

[Sleidia]

Hi

I have several multilingual websites that are encoded either ISO or Shift-JIS and I would like to convert them all into UTF-8.

What is the best step-by-step approach for achieving this easily and safely enough?

Also, my sites have content separated from the PHP code. Still, will I have to convert the PHP files into UTF-8 to make the whole thing work?

Thanks for the help!