Nice Wiki.
Everybody seems to work in a different way. I tried BookDesigner as Patricia said. I couldn't even start it. It was impossible for me to install on several different systems.
So I use BookCreator and after I'm finished I save it as striped HTML (It would be nice if there was a button for this) This HTML file I feed to Mobipocket Creator. That gives me the advantage that all books are in some kind of database on my PC. The resulting mobifile goes to my Cybook. I keep the HTML file also as a backup and a way to recreate when needed.