NOTE: Make sure you read the readme file in regards to 24-bit audio files as well as .aifc files.
After the file has been converted to AIFF or WAV, you can now bring them into iTunes. The downside, however, is that you'll lose the meta tag information in the process. You would have re-add the tag data after importing into iTunes. That, and they are substantially larger than the original lossless file. So it would be wise to have a really large hard drive if you expect to keep a large amount of AIFF or WAV files on your computer.
Also, if you're concerned about hard drive space and don't mind the quality loss from migrating from a lossless format to AAC or MP3, you can convert the AIFF or WAV file using your favourite AAC or MP3 encoder.
NOTE: Mileage does vary. The amount of quality lost when converting from a lossless format to AAC or MP3 depends solely on your hearing. One person may not find much of a difference between the original lossless file and a 128kbps AAC file while another person may find big differences between the same two files.
Previous hints should already tell you how to do this but personally, I use LAME for MP3, or Ovolab's AAChoo for AAC. That's, of course, you don't mind being beaned in the noggin by people who value the quality of .ape, .shn, and .flac files ... but that part is a totally different hint all together.
[daring attempt to be funny]
Next hint: How to dodge stones, knives, and bullets from people who shun those converting lossless files into AAC or MP3.
[/daring attempt to be funny]
Hope that helps.

