There are 3 types of message editors availible to edit and create posts.
You can get to them by clicking Quick Links and then Edit Options
Scroll down to the bottom where you will find:
Miscellaneous Options there will be a pull down box with 3 options for your editor.

Personally, I choose the WYSIWYG editor as it gives you a much cooler editing abilites but it is not supported in all browsers.

nJoy