Want a low power, small form factor PC, but want to build one yourself instead of paying Asus, Acer, MSI, Shuttle, or another company to do it for you? Asus has just released the AT3N7A-I motherboard which comes with a 1.6GHz dual core Intel Atom 330 processor and NVIDIA ION graphics.
The motherboard supports dual channel DDR2-800 memory, 8-channel audio, eSATA and SATA connections, and Bluetooth. There's also a single PCI slot, and an HDMI jack.
French site Blogeee has a detailed hands-on with the motherboard. You can find a bunch of pictures plus a detailed video which I've embedded below. Even if you don't speak French, it should give you a pretty good idea of just how small this mainboard is.
INTEL BOXDG41RQ LGA775 Intel G41 micro ATX motherboard 1xPCI-E(x16)/2xPCI/2xDDR2/integrated VGA/SATA/Lan(gb)
ASUS P5QPL-AM LGA775 Intel G41 micro ATX motherboard 1xPCI-E(x16)/1xPCI-E(x1)/2xPCI/2xDDR2/integrated VGA/SATA2/Lan(gb)
INTEL BOXDP55KG LGA1156 Intel P55 ATX motherboard 2xPCI-E(x16)/2xPCI-E(x1)/4xDDR3/SATA2 Raid/Lan
ASUS M3N78-VM AM2+ nVidia GeForce 8200 micro ATX motherboard 1xPCI-E(x16)/1xPCI-E(x1)/2xPCI/4xDDR2/integrated VGA/SATA2 Raid/Lan(gb)