Every text file is stored in a specific character set on disk. For your PHP files this must be UTF-8 charset **without [BOM](http://en.wikipedia.org/wiki/Byte_order_mark)**. Make sure to use an editor which is capable of Unicode. If you have some older non-unicode files in your project open them with your editor and save them again UTF-8 encoded.
> Tip: On Windows you can for example use [`Notepad++`](http://notepad-plus-plus.org/ "Notepad++"), which has an `Encoding` menu from where you can change encodings of your files.
On Linux you can also use command line tools like `recode` or `iconv` to convert a whole bunch of files. Here's a script that converts every php file in the directory `myproject/` and its sub-directories:
[...]
~~~
>Note: Unfortunately it's not recommended to set this ain an `.htaccess` file as this may lead to undefined behavior.
## 3. Database ##
Your database needs to know that it should store data in utf-8. The configuration for that might differ between database systems.