Ed Valentine (sweet name, whether it's real or not) takes a look at the improved Yankee fielding this year through the lens of advanced fielding metrics. It's a good read, and something I'm glad is appearing more often around the web. I really enjoyed the conclusion the article, too, which was refreshingly non-hyperbolized:
"Despite their errorless streak, the Yankees are not a 'great' defensive team. What they are is a 'solid' defensive team, which is a huge improvement over the awful defensive team they were in 2008. Last season the Yankees cost themselves runs -- and ultimately games -- by not being able to make routine plays. This year, they are making the plays they should make and occasionally making a brilliant play.
They may not be the best defensive team in the league. They are, however, helping themselves instead of hurting themselves. That's good enough."