With just a Webcam and a guitar, homegrown singers like Jayme Dee have turned their musical hobbies into Internet fame. Many times, these YouTube stars begin by covering (or making parodies of) popular songs.
Although some will argue that the original is always best, many of these independent covers are good--so good that you might want to download them to your iPod for the morning commute (guilty).
Nowadays, some YouTubers will provide an MP3 download link, but if that's nowhere to be found, use SnipMP3 to download any video as an MP3 (for your personal use):
Go to SnipMP3.com and enter the URL of the video you want to download. Then click "Convert to MP3." Finally, select "Download MP3" below the thumbnail of the video.
Note: Do not click the large, green "Download" button because it will download a third-party program without your permission.