Microsoft, Opera, and Mozilla have all teamed up in support of the Web Open Font Format or WOFF. According to the IEBlog they submitted the WOFF File Format 1.0 specification to W3C on April 8th 2010.
Any TrueType/OpenType/Open Font Format file can be losslessly converted to WOFF for Web use (subject to licensing of the font data); once decoded by a user agent, the WOFF font will display identically to the original desktop font from which it was created.
The WOFF format also allows additional metadata to be attached to the file; this can be used by font designers or vendors to include licensing or other information, beyond that present in the original font. Such metadata does not affect the rendering of the font in any way, but may be displayed to the user on request.
This would open up the web to any font a site designer chooses and not require the client to hold a bunch of fonts to make the site compatible. Two of the contributors to the possible standard are Tal Leming of Type Supply and Erik van Blokland of LettError; both are font designers that could see great benefits from something like this.