sIFR (or Scalable Inman Flash Replacement) has long provided an alternative to the default fonts available to web designers everywhere. However, it has also long provided endless migraine headaches, slowness, and other shortcomings.
Enter Cufón, a technology that aims to change all that without the need for a plug-in, and compatible with all type-a browsers. Let the tinkering begin!
[update]: Cameron Moll has a good post on using Cufón – the good and the bad.