hi Janne,
there aren't any books on Spring 2.0 (yet), but have a look at
http://www.springframework.org/documentation. There's a step-by-step tutorial that's a bit old but still good.
And Spring 1.2-code will still work with Spring2.0
(well at least in my applications).
You can then move on to the reference documentation for 2.0, which is pretty good.
If you want a book to begin with: Pro Spring (Apress).
I used all of these 3 when I learned Spring by adding Spring an existing webapplication(easier use of
JDBC, defining transactions and using AOP for logging)
Herman