Embedding fonts on the web is a big issue lately :). With the @font-face css rule you are able to use none-web-safe fonts on your site (.otf, .ttf on Safari and Firefox, .eot on IE).
Today Firefox is already supporting the WOFF format. It is ready for use in the next version (3.6). We are all hoping other browsers soon support it too.
So, as we believe this will be the next format for typography on the web, Typemytype endorses the WOFF specification, with default same-origin loading restrictions, as a Web font format, and expect to license fonts for Web use in this format.