James Whelton has managed to hack the lastest iPod Nano by bypassing the cache comparison, allowing black spaces to be created on the Springboard. This hack shows that the Nano has the potential to be jailbroken (in a limited capacity, at least), and may allow 3rd party apps to be used.
Next is the discovery in some of the device’s plists of reference to support of Movies, TV Shows, Apps, Games, vCards, Calender events and so on, with a few other cool things like a passcode lock. With the bypass I figured out, I hope to enable these pretty soon. It seems like the OS is a rehashed version of the previous Nano’s OS.
A tutorial is on its way in the next few days.