Sound effects can definitely enhance the experience. Unfortunately creating sounds that sound right can be a big waste of time.
Here’s a submission from Fred Shovell called Octave providing a free collection of sounds created for user interfaces. This project includes 48 different hand crafted taps, slides, and beep sounds that you can use within your mobile apps.
Few mobile apps make use of user interface sounds. Whether through lack of time, expertise or interest, not enough developers make use of it. Good sound can enhance usability and draw people into your app, just like well-considered UI or a beautiful icon.
Many developers lack the tools or knowledge to do sound well, and most free sound libraries suck. So we figured we’d make it easy for you, and put together a free pack of beautiful, simple sounds that can be used wherever you like.
Also included is a UIButton category that you can attach to easily play the sounds.
You can download Octave through the homepage here.
A nice free library with good sounds.