Winterboard - Give your iPhone or iPod Touch a graphical overhaul!
Alarmy - World's most annoying alarm app
Lockinfo - You can find this app in Cydia - Tweaks.
Galarm - Social alarm clock and reminders
IntelliScreenX - Need to know where your next meeting is? Do you have any new email?
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.