Rails 3 comes with some great new features and updates. One of them is a new DSL to describe routes. The DSL changed  quite a bit to Rails 2.0; in a good way. To get you started here some good sources about Routes in Rails 3:

Rizwan Rez from EngineYard

Railscasts Routing in Rails 3

Yehuda Katz: Rails Router 3: Rack it up

Rails Guides: Routes