I assume the only way to really tell is when I play an mp3 it actually shows 320kbps instead of the 1411(or something like that).

No, the way to really tell is to look whether the gears are turning on the main screen. Those gears are the "compression in progress" indicator. When they disappear, the compression is done.

If it's still compressing after a day, I'd reboot the machine, assuming the encoder thread is locked up or something. If there's compression left to be done, it'll pick back up again after the reboot (as far as I know).