This week, Microsoft surprised its Zune customers with an upgrade to the Zune PC software, bumping the version up to 4.2. Why was this surprising? Well, Microsoft did provided a heads-up about a system outage earlier in the week, but it wasn't supposed to be accompanied by an update of any kind. And when that update did arrive, it quite obvious included some interesting new functionality, though Microsoft refuses to even comment on it for some reason. And finally, there are clues in the installer files for Zune 4.2 that Microsoft is about to start supporting some mysterious new hardware devices that might or might not be the fabled Zune Phones.

Given the speculation around this release, I thought I'd take a closer look. But since Microsoft isn't talking, it's like that I'll have to update this article over time as more Zune 4.2 features become known. Here's what I know so far.