rspec users - Apr 2009 - RSpec and Selenium automation of an application

Hi All,
I am new to rspec and
I am using selenium with Rspec1.2.4, I have gone through describe, and
it methods etc.

I am automating an application which contains many testsuites and test
methods.

my question is

1. Should i write one describe method corresponding to one
testsuite ??? And one it() method corresponding to one testcase????

2. If Yes, then how would i execute more than one describe methods one
by one as same as running testsuites one by one If i want to keep each
describe() in separate file.