Rails 3

Now that rails 3 has entered beta phase, probably this is a good time to start learning about rails 3.

The official announcement:
Rails 3.0: Beta release

Installing rails 3

sudo gem install tzinfo builder memcache-client rack rack-test rack-mount erubis mail text-format thor bundler i18n
sudo gem install rails --pre

This is the canonical changes to rails 3:

Rails 3.0: Release Notes

This is a great introduction to rails 3:
The Path to Rails 3: Introduction
The Path to Rails 3: Approaching the upgrade
UPGRADING AN APPLICATION TO RAILS 3 — PART 1
Notes from the field upgrading to Rails 3

Rails 3 reading material:
Rails 3 Reading Material
Getting Up To Speed With Rails 3

Rails 3 compatible gem and plugin:
Rails Wiki


Apparently mongrel doesn't work with rails 3 yet, and also unicorn, the promising new kid on rails webserver battle doesn't work too:
Subject: [Rails] Edge Rails 3: Mongrel stuck in infinite loop, Unicorn missing uninitialized constant Rack::Runtime - msg#00437

So, you might want to use passenger 2.2.9 as rails webserver since it supports rails 3 already:
Phusion Passenger 2.2.9 released

Changes to rails 3 router & controller:
Revamped Routes in Rails 3
The Rails 3 Router: Rack it Up
What's New in Edge Rails: Default RESTful Rendering
What's New in Edge Rails: Set Flash in redirect_to
Generic Actions in Rails 3
Render Options in Rails 3

HTML escaping is now the default behavior:
SafeBuffers and Rails 3.0

New activerecord finder, you should really read this since a lot of finder will be deprecated:
Active Record Query Interface 3.0

New activemodel, basically this makes a model without a database table:
ActiveModel: Make Any Ruby Object Feel Like ActiveRecord

New actionmailer API:
New ActionMailer API in Rails 3.0

Edit:

Rails 3.0 Beta: 36 Links and Resources To Get You Going

Have another good link about rails 3? Feel free to comment.