An out-of-the box installation of MySQL already includes a great deal of support for both single and multi-byte languages, but a few enhancements in version 4.1 will enhance your experience even more.
Primarily, in MySQL 4.1, you will be able to define character sets on a percolumn, per-table, and per-database basis. This enhancement will allow for greater consistency and flexibility when developing internationalized application and multilingual Web sites. Additionally, MySQL 4.1 will offer Unicode (UTF8) support.
For more information on enhancements related to character sets, please see the MySQL manual at http://dev.mysql.com/doc/en/Charset.html.