I just wrote a small how to on how to make wordpress wordpress on a "NATed" server. I have implemented this technology into an open source project called qy.share and wanted to share it with wordpress users, as I got a couple of request on this specific part of the project.
I didn't post the full how to here, as it is quite long, and hope that moderators won't see any issues with this. I am ready to make a full article on this subject.
Anyway if you get there http://secondnode.qyshare.com/?p=211, you will learn the basics needed to host your favorite CMS behind a NAT and at home. It did work anyway, as secondnode is hosted in my living room behind a NAT ;).
Have a great day, and do not hesitate to post here any questions, or on secondnode, on how it works. Please apology for the english into the how to, and the code quality which is quick and dirty, and focus and making work wordpress rather than being solid like a rock.