Shawn Hargreaves Blog
I don't usually bother linking to things that already exist elsewhere, but I totally missed this announcement, so I figure you might have too. My apologies if this is old news!
We updated several Content Pipeline samples to take advantage of the automatic XNB serialization feature in Game Studio 3.1.
The 3.0 versions still work fine if you run them through the project upgrade wizard, but the 3.1 versions are simpler and easier to understand. Especially the Authoring Particle Systems Using XML and the Content Pipeline tutorial, which used to be a scary beast containing two different projects and an assortment of subtle shenanigans, but now takes hardly any code at all to do the same thing.