Mac OS or OS X users have a number of options for converting YouTube videos to MP3 and downloading them to their hard drive without downloading any software. SaveYouTube.com, BenderConverter.com and YouTube-MP3.org all convert the Flash Video embedded in YouTube URLs on their own servers before allowing you to download just the audio. This is a handy tool for downloading live music or alternate recordings of songs not available on CD, and is perfectly legal as long as the file is not copy-protected.
Open the YouTube page containing the desired video. Highlight the page's URL, right-click and select "Copy."
Open a new tab in your Web browser and visit SaveYouTube.com. Right-click the input URL field and select "Paste."
Click the "Download" button. SaveYouTube will download the video to its server and load a list of available download links for different formats. This may take several minutes, depending on the length of your video. If a warning dialogue box appears, click "Run" to continue. This does not install any software on your computer.
Right-click the "MP3" download option when SaveYouTube.com has finished converting the video. Select the "Save As ... " option to open a Finder pop-up window. Name your file and choose a destination on your computer to save the MP3. Click "Save" to download your MP3.
Visit the YouTube page with the desired video. Highlight its Web address, right-click your mouse and select "Copy."
Open a new tab in your Internet browser and visit BenderConverter.com. Click the "Convert By URL" tab near the top-left corner of the screen.
Right-click the "Video Page Link" field and select "Paste."
Select "MP3" from the list of "Convert To" options and click the "Convert" button. Wait for BenderConverter.com to download and convert the file.
Click the "Download" button when prompted by BenderConverter.com to save the MP3 file to your Mac.
Open your Internet browser and visit the page containing the desired YouTube video. Copy the URL at the top of the page.
Visit YouTube-MP3.org and paste the URL into the empty field at the top of the page. Click the "Convert Video" button and wait for the site to download and convert the video.
Press the "Download" button in the "Video Successfully Converted to MP3" portion of the screen to automatically download the MP3 file.
Most Mac OS or OS X users will find the MP3 in your computer's "Downloads" folder; however, this location may have been moved, depending on your browser's configuration. If you don't find your MP3 in the "Downloads" folder, open a new Finder window and click "Today" to view the most recent opened or downloaded files.