I was going to write up a nice article/tutorial on this but I knew it has been written about many times over. Not too mention it is in almost every Eclipse book on the planet. Many Notes developers still do not realize that most of the extensibility in Notes 8.x is really just plain old Eclipse extensions – preference panels being one of them. Eclipse.org is always the place to find the best small articles, this article is specifically about preferences – the store and the user interface.
The following tutorial post by Raja is also a great start in learning this stuff. So if you want to create Eclipse plug-ins for Lotus Notes make sure you check out what is available in the online community. I found this article by searching “creating an Eclipse preference panel extension” in Google, unfortunately it was found on the second page, near the bottom. So in short, I think this stuff is very hard to find and this kind of information is most likely not included in the Notes 8.x documentation. Your best bet is to search Eclipse.org!