There is several tools to help you, I have listed some below and there purpose
1. Mysql Query Browser (I use it for regular database editing, you can find it at mysql.com)
2. PHPMyAdmin (It runs through a web server using PHP, VERY Nice)
3. EQEditor - Used to edit the player profile in the `character_` table. This is a must have (I also built it), check it out at
http://www.sourceforge.net/projects/emueqeditor/
4. PEQ Editor - Used to help editing NPCs, Item Loots, etc. Find it at
http://www.projecteq.net