Follow the S60 Platform: C++ Coding Conventions document. Read the Internationalization section in that document.
The coding details are explained in S60 Platform: C++ Coding Conventions.
Use AVKON components whenever possible.
Most of the writing system and language support has been embedded in AVKON.
Use the TLocale class when dealing with locale sensitive
data (collation, different formats).
The TLocale class contains most of the relevant
functions and settings needed for smooth internationalization.
Use CharConv when dealing with character conversion.
CharConv contains the S60 supported encodings and
their conversion routines.