Downloading videos from YouTube in MP3 format is easy; all you need is a program called Download Helper. This program allows you to download videos from any site that hosts videos. You can download the videos in MP3 format and other high-quality formats, such as WMV, AVI and NTSC. You will need the Firefox Internet browser for this program.

Downloading A YouTube Video In MP3 Format

If you do not already use Firefox, go to mozilla.com (see References) to download and install it. Once you have downloaded Firefox, go to downloadhelper.net and click on "Add To Firefox." Follow the instructions to install Download Helper. A small rotating red, yellow and blue atom icon will appear on the Firefox toolbar when the program is installed. Now go to YouTube.com (see Resources) and open the video that you would like to download. Click on the little arrow next to the rotating atom icon in the Firefox toolbar. The video that you want to download will appear under the arrow. Note that if you have watched several videos, more videos will appear under the arrow. If this occurs, hold your mouse on the title and several tabs will appear to the right: "Download," "Quick Download," "Download & Convert," "Tweet this Video," among others. Click "Download & Convert." This will bring up a small window titled "Converter Options." Expand the section and a list of different formats will pop up. Select MP3 and save the file to your computer. Now you have the MP3 version of the YouTube video on your computer.

Source:

Mozilla.com: Firefox Download Site

Downloadhelper.net: Download-Helper Download Site

Resource:

YouTube.com: YouTube Homepage