Introducing sIFR: The Healthy Alternative to Browser Text describes a method based on JavaScript, CSS, and Flash to free text styling from the limitations of CSS and use any fonts.
The technique works similarly to CSS image replacements, except that the replaced text can grow with the page (e.g., if the user has set a larger base font). If a visitor has Flash and JavaScript available, correspondingly marked text areas are replaced by a Flash rendering.
If the visitor has no Flash or JavaScript is disabled, they will see normal text content via the browser's capabilities. Accessibility is thus largely preserved - the HTML remains semantic, and screen readers for text browsers as well as semantically controlled HTML readers should have no problem with it. Visually impaired users with large fonts can also benefit - for example, by disabling Flash, the user's chosen font size will be selected.
It is definitely better than CSS image replacement for headers, as it can adapt to the dynamic environment much better. Image replacements are not zoomed and do not support copying and pasting of content (which is also supported by Flash).