Or just forgo the native alarm clock app and use FlipClock, which lets you set alarms that are triggered by AlarmD, but also gives you the ability to just turn them on and off (without having to muck around at the shell level, delete/re-enter them, etc):
https://garage.maemo.org/projects/flipclock/
It's also available from the extras-devel repository (will pull in dependencies automatically if you install from there).

It requires Python2.5, PyGame, and python2.5-gstreamer packages to work (it's not in extras yet so unfortunately dependencies can't be automatically pulled in), but if you haven't got these already it's just a matter of red pill/apt-get commands.