Is there a video downloader or a way to listen to music like iTunes on chromebook?

Video downloader- of the internet on to your laptop

iTunes- like a media player so I can download songs on to it and update them on to my iphone

You may try this online video downloader. I always use it to download and capture video from websites. This tool can also convert the video to mp3 song for iTunes.
http://www.youtubetoipod.biz/best-youtube-converter.html
Hope it helps. Feel free to email me if you need further help.

Try vDownloader for mac.

http://www.google.com.au/...3&ie=UTF-8

You can download music from Youtube with mp4 or mp3 files and much more.