I used XLD pretty much exclusively to rip CDs for use with JRiver Media Center for Mac. For MC to see the files that XLD rips, they have to be in a location that MC knows about. As Jim said, they also have to be in a format that MC understands, but that's pretty easy, as MC understands just about everything from MP3, to FLAC, to AIFF, to WAV, etc.
I've got XLD set up to rip new files into a artist/album folders under my Music/FLAC folder. Obviously I'm ripping CDs as FLAC. In MC, go to:
Tools -> Options -> Library & Folders -> Configure Auto Import
In the dialog that comes up, add the parent folder where you are ripping your CDs to. In my case it's /Users/bgentry/FLAC . Now any file I put under that directory, even if it's in a subdirectory (like The_Doors/Greatest_Hits) will get automatically imported and recognized by MC.
Hopefully that gets you started in the right direction. XLD and MC are great programs that work fine together.
Brian.