Here's a look at the soon-to-be-released Firefox 3.5 support for @font-face:
http://hacks.mozilla.org/2009/06/beautiful-fonts-with-font-face/
Of some interest:
By default, Firefox 3.5 only allows fonts to be loaded for pages served from the same site. This prevents sites from freely using fonts found on other sites. For sites that explicitly want to allow cross-site font sharing, an online font library for example, Firefox 3.5 supports the use of access control headers to control this behavior.
There is a section on "respect for font licensing", though it's glossed over - which is probably for the best since it's not the browsers job to enforce i.p. (IMHO).