This has been discussed several times. It appears that functionality is missing in ML. You could try an alternate app, such as TotalFinder. There are also some ideas in this thread:
For that matter, opening in iTunes would show it. I think the issue is that Finder doesn't show it, and some want to know the bitrate without having to actually open each file.
For that matter, opening in iTunes would show it. I think the issue is that Finder doesn't show it, and some want to know the bitrate without having to actually open each file.
Agree that they should put it back in Finder, but short of that I'd still suggest opening it in Quicktime rather than having iTunes auto-import and copy it (which is how most people have iTunes set).
For that matter, opening in iTunes would show it. I think the issue is that Finder doesn't show it, and some want to know the bitrate without having to actually open each file.