I used to use this on a PC to record streaming radio. I now use the Mac version occasionally (when Radioshift fails - again). On the PC there was a nice workaround which allowed you to set up a recording, so that it stopped at a required length of time. You would open a new track, view the amount of time you wanted to record and then drag your mouse pointer from the beginning of the track, to the desired time length.

Hope I am making sense! Anyway, this doesn't seem to work in OS X. Anyone know why, or another way to do it?