[gord]

You know CSS, so it seems logical to learn Javascript.

That opens up both server and front end web programming [jQuery/DOM and Node.js on the backend]

For books, try Crockfords 'Javascript the Good Parts' and mimic some of the nicer idioms as you see more jQuery code.

[jessor]

I found "JQuery For Absolute Beginners" to be quite helpful for getting familiar with JQuery: http://net.tutsplus.com/articles/web-roundups/jquery-for-abs...

[desigooner]

I'll second that. NetTuts has a nice video series on jQuery that is pretty lucid to understand.

[RDDavies]

Also, http://www.amazon.com/JavaScript-Definitive-Guide-Activate-P...

6th edition of Flanagan's Definitive Guide coming out.