I strongly recommend that people only use this technique if they are dealing with lossless audio files. Doing this with lossly audio (mp3, AAC, OGG ect) will result in transcoding the data. meaning it will have been encoded twice. See the Wikipedia Article on transcoding for why this is bad.
You will need to have a copy of toast 7.0 or above in order to do this.
This trick might not work if you FLAC files have not been properly ripped. please see the other article on properly ripping FLAC on a mac.
Now we will create a disc image from the files.
After it is done writing the disc image
iTunes Should Now get the official CDDB tags for the tracks. If it didn't there are a couple reasons this could happen.
From my understanding, the CDDB uses the combination of track lengths and track numbers to determine what CD it is. I am not sure if subtle disc read offsets will make it unrecognizable or not.
After you import your CD however you like, unmount the disc image and delete it, you will never need it again, as long as you keep the original FLAC files.
Personally I compress all of mine FLAC files to V2 with iTunes-Lame. Then i burn all of the FLACs to DVD. I am sure there will be a day when iTunes or OS X has better support for FLAC and would rather not get involved with Apple's slightly icky ALAC format. The real benefit of this approach it that i can just delete my compressed mp3s any time i am short on space and if i want them back, i can just re-encode from the burned FLAC files.