As I mentioned above, dyndns is not the optimal solution. dnydns.org does not support dns service discovery.
http://www.dns-sd.org/
Normal link-local bonjour uses multicast dns to do service discovery. (eg. what airdisks are available on this network). Bonjour over the WAN relies on having a dns server configured with some apple extensions that let applications "register" their services with a central dns server that then keeps track of different service types. Usually this registration is controlled via simple authentication (username/password). Then, I would configure the bonjour pref pane (
http://www.dns-sd.org/ClientSetup.html) to register my hosts services (itunes shared library, ichat bonjour, ssh server, web server, etc) in a specific domain. Then when another client that is configured correctly fires up an application that supports bonjour (like itunes) not only will it see itunes shares on the same subnet, but it should also see ones that are in bonjour dns-sd/wan domains that my host is configured to query.
You can only register services in one domain, but you can query multiple domains.
So, what I want is to have something like dyndns.org, but would let me use it to register my services (like my airport extreme connected printers and airdisk) so that when I am at work, I can use the airport disk utility menu bar item to mount my drives from home at work.