Not exactly the best written introduction to the tool, but we use Sonar locally and it's pretty decent. Everything it does is done by some individual component, the advantage of Sonar is that the results are more generally accessible. I don't use it as much as I ought to because my mutant power is being able to keep our codebase more or less in my head, but it's useful for the less blessed members of the team.
A nice clear sales piece. We should all aspire to such a well explained benefits page.