Hi!
I decided to start learning to develop rich internet applicatons little by little. I mean applicatons that copy desktop-like interface, not jquery/prototype-powered websites.
After a lot of thought and googling i came to ExtJS. It appeared to be THE frontend for my purpose: popular, full-featured, well-documented.
I found out that there is no backend developed specially for ExtJS (or at least with ExtJS in mind). ExtJS suggests developers to take care of the backend on their own — reasonable for an experienced web developer, but not for a newbie.
And i found no tutorials or guides that would teach building a backend based on any server-side language/framework.
Of course, all server-side frameworks like Zend, Yii, CakePHP, Django,
Rails are ExtJS-capable. But all of them require some (or many) effort
to pair with ExtJS: write helper functions and classes, overcome
differences in conventions and concepts. Because all of server-side
frameworks are designed for usual html/css sites and JSON/REST is only
a side-feature. 
But after some investigation i learned that Rails is much easier to work with ExtJS out of the box than any other framework! Yay! But still it's going to be a lot of pain for me: i'm scared that i'll have to learn two totally separate technologies based on two different languages i'm absolutely not familiar with.
MY QUESTION IS: what should i start with on my way of learning the development of rich internet applications with Rails+ExtJS?
PS As for my level of noobieness, i have very little experience in coding but i had some fun with PHP. But i have a good understanding of MVC, of using abstractions. I'm also familiar HTML/CSS (though it seems i'm not going to need that with ExtJS) and a little Linux administration (i'm hosting my own Drupal sites on a dedicated Linux server).
PPS ExtJS supposes using Eclipse as an IDE. Does Ruby/Rails have full- featured support in Eclipse? Don't want to use two IDEs...