I purchased the Ambiance app (link opens in iTunes) for my iPhone a few weeks ago ($0.99) and although some of the noises seemed pointless (White Noise, Blue Noise, and Violet Noise all just sound like static!) some of the noises were really nice, like the Birds, Stream, Waterfall, and Waves.
Last night I "discovered" there was a built-in timer! This meant I could leave a noise on for an hour while I'm falling asleep and it would automatically turn off. So last night I turned on the Waves sound and went to sleep. It was amazing how I could close my eyes and instantly imagine myself near the beach with real waves rolling in.
I also use my iPhone as my morning alarm, so now I have two uses for it related to sleeping. 🙂
jailbreak = ability to install cracked apps + more apps with cydia + installer that arent available on appstore ! lots of customizing options once you jailbreak .