Database Management: phpMyAdmin

phpMyAdmin is an incrediably popular tool for online, graphical database management. It is considered one of the "must have" features of any web host supporting MySQL.

From the phpMyAdmin webpage:

phpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web. Currently it can create/drop/alter tables, delete/edit/add fields, execute any SQL statement, manage keys on fields, export data into various formats and is available in 50 languages. GPL Licensed.