ToneFXs 2 (Pro) [correct spelling] is a tweak for iOS that will allow you to control almost all the sounds on your device. You also have the ability to create your own which is a nice feature to add. You can download the ToneFXs client at their website to help you create sounds too. The tweak itself is a bit pricey for what it does at the price of $4.99, but if you are "Social Network King/Queen" this can be pretty useful. You can set tones to specific contacts so you always know who is contacting you as long as you remember. Check out ToneFXs 2 (Pro) in Cydia.