ALTER TABLE tbl_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

  HOW TO MIGRATE DATABASE FROM MYSQL 3.23 INTO MYSQL 5.0


+--------------------------
| Why

1. db format has been changed
2. UTF-8 has been native used from version 4.1
3. password function has been improved


+--------------------------
| How to

1. dump the database from mysql 3.23
mysqldump -u root -p database > database.db

2. convert to UTF-8
iconv -f cp1250 -t utf8 < database.db > database.utf8.db

("from" code page may vary...cp1250, czech, win1250, latin1, latin2...)

3. modify the dumped file
replace:
TYPE=MyISAM;
by:
DEFAULT CHARACTER SET utf8;

4. create empty database in mysql 5.0
(mysqladmin -u root -p drop database - if needed to drop a previous version)
mysqladmin -u root -p --default-character-set=utf8 create database

5. import converted database dump
mysql -u root -p --default-character-set=utf8 database < database.utf8.db

6. reset the database user's password or use the OLDPASSWORD function