For those (lucky) enough to have an Intel Core based Apple machine (like me as of this morning, exciting stuff!), these are some useful links for Universal Binary versions of the major Mozilla programs:

Mozilla Intel Wiki Page
Information and download links for Firefox and Thunderbird (experimental builds only at present).

Camino Browser Page
Stable, universal release of Camino now available. My favourite web browser :).

My killer combo is Camino and Thunderbird; Camino because it uses the same engine as Firefox but uses Cocoa so it loads faster and looks sexier, and Thunderbird because it lets me take all my email data and profiles to a Windows or Linux machine very easily.