Are you interested in creating a megadungeon for your campaign world?
Here are some links that I found, which may be of use to you:
http://beyondtheblackgate.blogspot.com/2009/08/megadungeon-design-and-philosophy-part.html (This is a series of posts, with links to the next of the series at the bottom. All of the posts in the series are worth reading.)
http://www.therpgsite.com/showthread.php?p=504466 (If you follow no other link, I would encourage you to read through this thread. It is excellent!)
https://panzerleader.wordpress.com/tabletop-tableaux/ (A number of interesting articles related to megadungeons and 4e. Worth a look.)
http://www.philotomy.com/#creating_dungeon (Philotomy’s musings are well worth the read!)
http://www.therpgsite.com/showthread.php?t=21819 (Links to additional resources.)