It is UNBELIEVABLE that Abode Soundbooth does not support flac.. Use this to fix it: download this: http://valion.net/flacimporter/ or x64 version http://valion.net/flacimporter64/ then copy the "FLAC Importer.prm" file from "C:\Program Files (x86)\Premiere FLAC Importer" or "C:\Program Files\FLAC Importer 64" to "C:\Program Files (x86)\Adobe\Adobe Soundbooth CS5\Plug-ins\Common" restart the program and you should be able to import FLAC files.
This should work similarly with other Adobe programs like for example Premiere Pro.