You should check the forums on the HTMLArea website at http://www.htmlarea.com
. Everything I've needed to know about HTMLArea I've found there.
My installation of HTMLArea is pretty customized, so I don't think sharing my code with you will help.
If you have trouble with the installation search in the HTMLArea forums. I've been able to solve every problem that's come up by referencing the forums (albeit sometimes it takes a lot of digging, but there is a wealth of information there). There were quite a few bugs with Mozilla/Firefox that I fixed by searching these forums.
Mail_IMAP: A PHP/C-Client/PEAR solution for webmail
Author: Beginning CSS: Cascading Style Sheets For Web Design