MP3Gain

[CGSDR]

Hi, I'd to introduce this program, for people who like to increase their MP3's sound or volume, you will able to do with this program, here is the link: MP3Gain, I've been finding a good and free software that could increase volume of a mp3 song just like iTune do, and I can assure you that you will be happy with this program just like me.

Here is some summary of what this program can/will do:
MP3Gain does not just do peak normalization, as many normalizers do. Instead, it does some statistical analysis to determine how loud the file actually sounds to the human ear. Also, the changes MP3Gain makes are completely lossless. There is no quality lost in the change because the program adjusts the mp3 file directly, without decoding and re-encoding.

*Please Note That This Is A Freeware, It Has No Charge Of Money*

[PirateEggs]

Audacity is a nice audio editing program too.
It's completely free...

[CGSDR]

Yeah I know but this program is a light weight one it's consume only 1.08MB in Size but it has the MP3 volume increase function only.