I haven't had a chance to test this yet, but I had to send you in the link. Configuring clients to use Wide-Area Bonjour contains a link to a Bonjour Preference Pane for Tiger. From the site:

The Bonjour Preference Pane provides a user interface for using the wide-area aspects of Bonjour. The customer releases of Mac OS X Tiger and Bonjour for Windows include full wide-area Bonjour functionality for developers to utilize in their applications, but no user interface. The Bonjour Preference Pane allows you to set system-wide defaults that will cause standard unmodified Bonjour applications to browse for and/or register network services in wide-area Bonjour domains, rather than only on the local link.

I haven't had a chance to test this yet because I need to configure dynamic DNS on my server. I hope that the Wide-Area Bonjour includes service discovery, because then I won't have to jump through so many hoops to keep all of my macs on the same local link. Be sure to also check out Setting up a Bonjour Name Server for a description on setting up a server to support wide-area Bonjour.

[robg adds: I haven't tested this one either, but it seems quite cool. Note that you will not be able to browse iTunes shares nor use iChat's Bonjour chats in wide-area mode.]