I use Winamp, and it tells you the bitrate of the file you are playing. If I hit the "Launch" button underneath the download window, LimeWire will launch Winamp and have it play the downloaded portion of the song. I can then read the bitrate information given and decide whether to cancel the download or continue with it. :-) Your download won't be interrupted while you preview it with the "Launch" feature.

Hope this helped!