You could edit the FLAC files themselves with any number of editors. Audacity is free and very popular. It works well, but maybe isn't the most friendly.
Or you could do it inside of MC with a tag setting, telling MC to only play part of the song. Highlight a song, open the tag editor, and go find the tag named [Playback Range]. You can type ranges in there like:
0:10-4:20
0:30-
The last one says to start at 30 seconds in and play until the end.
Good luck.
Brian.
