JavaScript is the global web version of the unix shell script, simply increadibly useful. With tools like ubiquity and greasemonkey you can do lots of cool stuff. Also all the nice frameworks, GUI components and the JSON APIs makes it a very useful language.
So to help you learn JavaScript and for my own reference I have listed some really good resources
The JavaScript Programming Language
http://video.yahoo.com/watch/111593/1710507
http://video.yahoo.com/watch/111594/1710553
http://video.yahoo.com/watch/111595/1710607
http://video.yahoo.com/watch/111596/1710658
Advanced JavaScript
http://video.yahoo.com/watch/111585/1027823
http://video.yahoo.com/watch/111586/1027832
http://video.yahoo.com/watch/111587/1027854
JavaScript – The Good Parts
http://video.yahoo.com/watch/630959/2974197
Interactive tutorial by John Resig:
http://ejohn.org/apps/learn/
JavaScript best practices
http://www.slideshare.net/cheilmann/javascript-best-practices-1041724
Blogs:
http://www.robertnyman.com/
http://www.wait-till-i.com/
http://remysharp.com/
http://frontendbook.com/
http://mattsnider.com/
http://ejohn.org/