I'm actually working on a QT component to play FLAC along with another programmer. The two of us have been in touch with the programmer of the OggVorbis QT component and will likely include FLAC as another CODEC within that component.

Also, iTunes hasn't opened up its API for registering alternative codecs for ripping audio. This is unfortunate, but we hope a future version of iTunes will make this possible.

Follow the progress of the FLAC component on my blog at: http://radio.weblogs.com/0134505/categories/CoreAudio/

There hasn't been an update recently, but it's coming. Patience, please.