The internet is a nice source for utilities. I have been an avid collector of MP3 songs - especially hard to get ones. Unfortunately, not all my MP3s are at the same volume. So i need to keep up-ing or down-ing my volume from time to time. Well, not any more. I discovered this open source tool called MP3Gain which lets you normalize your song files so that they all play at the same volme. More details on the site.