jQuery worths learning!!! I recommend reading "Learning jQuery" and "jQuery in Action". Both books are great with expalanation and examples. The next step is to actually use it to do something. You will find official http://docs.jquery.com docummentation very useful. I use it as a reference, google it all the time :)
Also "Learning jQuery" blog mensioned by Sean is also very useful. Also jQuery HowTo is also has a great collection of jQuery code snippets.