Loading site-specific CSS files into Sitecore's rich text editor

See more:

CSS

SQL-Server

ASM

RichTextBox

I have a text box and I am using richtexteditor like CkEditor or Ajaxhtmleditor.
I would like to actually define the css styles and apply it to the text in the textbox so that when the data is submitted to database, the styles are applied and rendered with the styles i have applied.
Just like the one I am writing this question in this textarea and applying the styles from the above texteditor control.

Any suggestions or solutions would be helpful.

Thanks!!!!