Here's the simple version:
The brains of two rats are connected by an Internet-based communications channel. Scientists taught one of the rats how to solve a simple puzzle. When confronted with the same puzzle, the other rat went straight to the answer; the scientists believe the first rat passed the solution to the second across the link.
For instance, one of the rats was taught how to obtain a drink of water; confronted with an identical situation the second rat immediately knew how to get the drink.
The report is presented in its entirety here.
What this means is that what the first rat learned, the second rat could immediately use to its advantage.
All manner of uses have been suggested to arise from this from the fanciful to the incredibly useful. For instance, it may serve as a tool for patients with locked-in syndrome and, at the other extreme, it may be the precursor to some form of hive mind, involving all humanity connected to a single interface. Who knows, perhaps Skynet actually turns out to be us!
"I don't think there's any risk of supersmart rats from this," said Anders Sandberg, who studies the ethics of neurotechnologies at the Future of Humanity Institute at Oxford University. "There's a big difference between sharing sensory information and being able to plan. I'm not worried about an imminent invasion of 'rat multiborgs'."
The obvious question (to iTWire at least) remains unanswered; what is the nature of the signals transmitted between the two rats? This requires us to ask, what exactly is a thought, a memory, an action; how is it expressed in data; in numerical form?
Clearly this is an early step in a very long line of research.