Syntax:
ALTER DATABASE [db_name]
    alter_specification [alter_specification] ...

alter_specification:
    [DEFAULT] CHARACTER SET charset_name
  | [DEFAULT] COLLATE collation_name

ALTER DATABASE enables you to change the overall characteristics of a
database. These characteristics are stored in the db.opt file in the
database directory. To use ALTER DATABASE, you need the ALTER privilege
on the database.

The CHARACTER SET clause changes the default database character set.
The COLLATE clause changes the default database collation.
http://dev.mysql.com/doc/refman/4.1/en/charset.html, discusses
character set and collation names.
