Kastor Youtube To Mp3 - Version 1.2 Kastor Youtube To Mp3 is a completly FREE Software. Download Youtube videos directly to mp3, wma, aac...It lets you download and extract directly the soundtrack of Youtube videos.Up to 20 simultaneous downloads.Nothing could be simpler, just copy and paste the address of the youtube video in the software and go !With the Firefox extension, it's even easier: a simple right click on the YouTube page, then click on "Download video as Mp3"Very user friendly interface and very simple to download all Youtube clips you want !