Unable to get CKEditor to work using Drupal 7
Here are the steps that worked for me on Drupal 7.7


Instal the WYSIWYG module and enable
Download the latest CKEditor and unzip it in sites/all/libraries
Go to configuration => wysiwyg and choose the editor for the input format (use it on the full HTML or PHP)
Now you can edit and there you can choose under buttons and plugins what buttons appear
When you create a content type don't forget to set the correct text format 


btw a while back I had a problem where the WYSIWYG used the background from my site. I had to change the CSS settings, below buttons and plugins, and set it to use editor default.