I had troubles with FCK editor showing different fonts than the skin did. After a lot of messing around I figured out that DNN jams you into the .Normal class to start with in the Text/HTML module, while FCK thinks that the definitions in "body" are the root of the world. 

I ended up doing two things:

• I edited the "static" to "dynamic" in the FCK parts of web.config to that FCK always used my skin's css definitions
• I edited my skin.css so that I had my default font definitions in one pages for "body, normal, normalbold ....."

This worked for most problems. However, I still had a few problem pages. Somehow they had a lot of <div class="xxxx"></div> for and not <p></p> for multiple end of line.  Ther also seemed to be some untended font definations. I cut  the entire page into Visual Web Developer, leaving giant DNN/FCKedit span. Then I did a mas conversion of these tags. Then I pasted it back inside of the remaining span.

This made the whole FCKedit world look better for me now! 

At the same time I restructured my css file so that:

• The physical layout was in one section, all by itself. Easy to visualize and adjust.
• I set the default style and size in the "body, normal ..." section above and made all other size references as a percentage or "em". Now I scale the page easially. This did mean that I had to override several of DNN's "default.css" definations which seemed to be a strange mix of pt, px, em and %.
• Each color used was only defined one or two times (color & background-color), and each class or div that uses that color was listed there. With this I could tweak the color easily to make new skin derivatives. I try to control the number of total colors in the skin
• I did finally keep the menu colors in separate, because I was messing with different menu systems, but they too are formated as above.
• I have a section for the various editing classes that are used on my site (.QuoteLeft, ImageRight etc). Now I can cut & pasted them from skin to skin as required.
• Had Visual Web Developer validate and format my skin.css. It is amazing how different tools and browsers deal with an exta "}" or other error. Then checked it with W3C's tools.

Hope This help with your FCKedit issues.  They are likely to be css skin issues in part.

/DaveS

Yes, there is a guide being built and there is an offering from someone to be in charge of the documentation. I just returned from vacations and want to establish contact again with the possible new team. So, there will be a new guide soon.

About the styles, a good skin must include the default font inside the most used tags and also inside the NORMAL related classes too.

FCKeditor manages styles by using two resources:

1) a .XML file that includes a list of attributes to list in the styles toolbar. This is just a xml file with a specific format described here: http://wiki.fckeditor.net/Developer%27s_Guide/Configuration/Styles

The provider has included tree ways of managing this xml info:

a) Static: The provider will use the standard .xml file located at: 
Providers\HtmlEditorProviders\FckhtmlEditorProvider\FCKeditor\fckstyles.xml

b) Dynamic: Each DNN page loads a set of style pages (Default, skin, portal, module, etc). By setting this option to dynamic, the provider will instruct the editor to use those styles. There is a possible REGEX filter to clean the styles list

c) Static: You can tell the provider to use a custom .xml file (Must follow the rules explained in the previous link). So you can include the styles you want and customize your own styles

2) As a second resource (optional bu somehow necessary), all the styles created inside the XML file that refer to a CLASS property must exist in the loaded styles at both sides: Normal page view and when editing. So those styles can be included at any of the already loaded styles by the page itself. Those styles must also be loaded for the editor and to be applied when editing. The provider includes tree ways to manage the editor loaded styles

a) Static: The provider will use the .css file located at:
\Providers\HtmlEditorProviders\FckhtmlEditorProvider\FCKeditor\editor\css\fck_editorarea.css

b) Dynamic: The provider will include all the DNN styles when editing

c) Static: You can define a custom .css file to be used

FINAL COMMENTS:

If dynamic styles are chosen, the default font will be the default font applied to BODY in your skin or replaced in your portal.css (Portal settings) . The static mode tels the editor to use the already explained default files, so you can define your default font there

So, it is really very easy to configure how styles are managed.

Hope it helps