Codebureau - Matt Simner

I've only recently started using JQuery, but needless to say - it rocks!

for those that don't know it's a Javascript library that's basically revolutionising how you write client-side code.  My reasons to love JQuery.

1. It's open source, well tested and an open design.  This means you write less code and you can rely on functionality just 'working' in different browsers - or gracefully failing if something's not right.
   
2. It's really light (especially when 'packed' - 31kb)
   
3. It's got a strong community with lots of really cool plugins (just take a look before you start developing that 'widget' in flash)
   
4. It plays well with other libraries and code.  you just use it for what you need and plugins sit with other plugins.
   
5. It's obviously gaining momentum, as Scott Hansleman announced Microsoft are going to ship it with ASP.NET MVC and Visual Studio (that's a pretty amazing move from Microsoft).
   

If you're just getting started with it, and you're familiar with Javascript already I'd start with the tutorials.  Some are better than others, but run through the first couple to understand how it works, then scan down the list to find something related to what you need to do.  Typically you'll be wanting to write a plugin, so I found this one quite good for starters.

You should find everything you need in the Documentation

you'll then spend most of your time in the API section, looking for specifics on how to do things.