(In response to an article by George  http://www.supplesoftware.com/articles/2006/04/16/dependency-injection-without-frameworks)

I have been a firm believer that Dependency Injection is a design principle, not a library you include.

Using a library is a good starting point if you or your developers are not familiar with dependency injection.  However, I have found a preference for more and more lightweight containers to the point where my containers are supported by a couple of helper classes which do as little as possible.  

Secondly, while libraries help DI, they don't guarantee it so developers have to understand what is DI and why are they using it in the end.  Forcing developers to think about what they are doing and why can lead to happier development because a desire to learn new techniques is motivater for most developers.

So I would say, look at the frameworks and get an understanding of what they do.  Pick the most lightweight one for your needs (even write a few classes if that is all you need) and you will get the most out of DI.