An Irish iPhone and Android developer has managed to bypass the Pre's activation, enter into a root shell, and discover that unsigned firmwares can be installed. The UI and apps are written in javascipt, so changes to the source code do not require recompiling. I know this because his blog says so, not because I know anything about javascipt. C and C++ native Linux apps can run on the device as well, as evidence by a Pre port of Doom.
The hacker is getting a lot of attention, as he "may just have the first jailbroken Pre in existence." This kid is so far ahead of me I don't don't know if he was dead serious or making a clever joke when he wrote, "you can use the Konami cheat code to enable dev mode, too); you can do whatever the hell you like to the OS!"
That's: up, up, down, down, left, right, left, right, B, A, B, A. Wikipedia doesn't specify an instance where both select and start are added to the end, so I'm not sure why that's how I remember it. Anyway, I can't wait to see the modifications and hidden features that are sure to unfold this Summer.