Rings Extended - Have you really ever wanted to make your ringtone a song but you're not sure how to do that? Rings Extended by Dianne Hackborn in the market will let you pick any sound file to be a ringtone or event notification.  Just install the app and when you go to change a notification sound you will get a prompt for what app to use (usually the Android system does this automatically) and pick Rings Extended.  You can download wav files or MP3's and make them your ring or notifications. 

https://market.android.com/details?id=com.angryredplanet.android.rings_extended&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5hbmdyeXJlZHBsYW5ldC5hbmRyb2lkLnJpbmdzX2V4dGVuZGVkIl0.