Late last night, we put up a post debunking the idea going around the Bloggerdom that the iPhone OS 4.0 Beta had already been jailbroken, because, well, it hadn’t.

But now it has.

MuscleNerd, a member of the notoriously wonderful iPhone DevTeam, pushed the above video out to YouTube this morning. What you’re looking at: that’s a VNC server running on iPhone OS 4.0, allowing MuscleNerd to remotely connect, view, and control it via his computer. Even with iPhone OS’ new found multitasking abilities, that’s something the iPhone just can’t do by default.

There’s little reason to doubt the authenticity of this video; MuscleNerd is amongst the most established members of the iPhone hacking community, and isn’t really known for messing around.

While it’s exciting to see, remember: this is Beta software. Apple’s presumably leaving whatever security holes they know about open in the Beta for the same reason the development team isn’t releasing the details of their most recently discovered exploits (including this one) until iPhone OS 4.0 is available to all: it’s a game of cat and mouse. The mouse doesn’t want to tell the cat where he’s hiding his cheese, and the cat doesn’t want the mouse to know whether or not she already knows.