I've been using DVD-Audiofile For my iMac. It uses David Chapman's dvda-author tool. It's a simple no-frills package that creates an iso image that you can use Toast or the Mac disk utilities to burn. I've created about 20 DVD-A's using this with files downloaded from HDTracks. It uses flac and wav files. Plus, its FREE. I downloaded it from;
http://mac.softpedia.com/get/Audio/DVD-Audiofile.shtml
Good Luck!