I am using a program called MPTrim Pro (http://www.mptrim.com). It removes any frames of digital silence from the beginning and end of mp3 files without re encoding them. I know it is not just setting new start and end flags in the tag because the file size is actually smaller after trimming the silence. Obviously it has no effect on live albums or some of the newer CD’s that are gapless but it does a great job on the older stuff that can have 5 or 6 seconds of nothing between tracks.
When you run MPTrim on a file it will show you the the file space saved before trimming and allow you to preview the first and last 5 seconds of the track. It also shows the new (trimmed) track time in seconds or frames. It actually shows separate values for time trimmed at the beginning and end of the track.
I can’t stand long gaps in music when listening to my SB.