Our whole application is now able to handle UTF-8 and it will be our choice in terms of encoding all across our architecture. The last step is to change the encoding of our MySQL databases.
Of course, ALTER TABLE db_table CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
should be able to convert each of the tables to the right UTF8 encoding, yet, is there anything else I should do? I believe that the my.cnf configuration file needs to be changed as well.