The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From P2 Digital:
iStrobe turns your iPhone or iPod touch into a portable strobe light. Its great for using in clubs, bars and festivals when you need to get noticed! In fact, it works great in any dark room so download this app now and get the party started. Features ********* Range of instant strobe effects Customizable settings for changing flash frequency Changeable colors. Compatible with latest iOS Important In order to allow iStrobe to work best, go into the phone settings, go to brightness and turn off Auto-Brightness as the phone will try to dim in the dark. You may also wish to turn the brightness slider to the fullest. WARNING: as with all flashing lights, dont use if prone to seizures.