I need several alarms during the day and week. I've tried a number of different apps, and HD Widgets works best for me. You need to use a 2x1 size widget, then select the clock option and configure the appearance how you want it. Once you've installed it, a new screen opens whenever you click on it and you can add alarms, edit their time/day settings, switch them on/off individually etc.
HD widgets is quite versatile, with numerous size and configuration options. For example with a 4x1 size widget, you could configure it to show time and date and have the time bring up the alarm and the date part bring up your calendar.