We are using sIFR on a few of our sites, and people seem to be asking about it a lot recently. A short description and links below.
sIFR is meant to replace short passages of plain browser text with text rendered in your typeface of choice, regardless of whether or not your users have that font installed on their systems. It accomplishes this by using a combination of JavaScript, CSS, and Flash, which renders the font. It degrades gracefully if Flash is not present.