If you thought nettops were cheap, wait until you get a load of this: Marvell has announced the SheevaPlug, a $99 reference design based on the company’s own "plug computer" concept. In short, this system plugs directly into a power socket, much like a glorified wall wart with Ethernet and USB ports.

Marvell says the SheevaPlug reference design includes a 1.2GHz, ARM-based Sheeva embedded processor, 512MB of DDR2 memory, 512MB of flash memory, Gigabit Ethernet, and USB 2.0. If you were wondering, yes—Marvell does design processors. As a matter of fact, it acquired Intel’s XScale business back in 2006, and the former XScale team seems to have contributed to the Sheeva design.

On the software side of things, Marvell notes that the SheevaPlug supports "multiple standard Linux 2.6 kernel distributions." That should make running and developing software for the platform pretty straightforward.

Speaking which, developers can get a SheevaPlug development kit for $99 right now by heading to Marvell’s website. Other folks will probably want to wait for actual products based on the design—and there are several in the pipeline, including the $79 CloudEngines Pogoplug and the CTERA CloudPlug. According to the Wall Street Journal, Marvell expects prices to go down to $49 eventually.

Check out the image gallery below for some photos of the SheevaPlug reference system and a diagram showing a possible usage scenario. As Marvell points out, this hardware should be a nice way to turn an external hard drive into a network-attached-storage solution. A tiny, ultra-cheap Linux network PC can probably serve many other purposes, though.