The multi-color sIFR v.20060623 [.ZIP 36KB] currently supports <a> (also in the official version), <strong>, <em> and <span> elements1. There are also a few usability improvements2.
For general info about how to use sIFR, please refer to sIFR wiki.
Multi-color sFIR implementation is easy – just add sEmColor:"#FF4400", sStrongColor:"#FF0000" and sSpanColor:"#EE6600" into you named argument call function at the bottom of the .html file and if the script finds a <strong>, <em> or <span> elements, each one will be colored3. And they can be nested, too.
class, title etc. will do no harm..swf files and replace the old sifr.js with a new version.