As designers, and in working with our design agency partners, we have often been confronted with some level of frustration in the limitations of our web choices. While sIFR (or Scalable Inman Flash Replacement) was an alternative technology to consider, its dependence on Flash has pretty much ruled it out if we need to support iOS mobile (which we do).
With the rise of services such as http://typekit.com/ (free or paid) or http://www.google.com/webfonts, designers' choices of web fonts are been broadly expanded. So there is no longer a need to rely on image > text conversion alone (which isn't feasible in any case for dynamic text such as menus).