MCP73 chipset has been announced for some weeks. To date, there aren't any boards out there as chipsets are still in the process of being debugged and delivered.
The I-N73 series comes in two flavours, the I-N73HD comes with 1394 while I-N73H don't. Both are based on NVIDIA MCP73PV chipset.
The I-N73HD supprts the next generation 45nm multi core Intel CPU wiht FSB of 1333/1066/800. It supports all range of Core 2 Extreme, Core 2 Quads and Duos, including Pendium D and Pentium Dual Core and Celeron processors.
The board supports single channel memory architecture with 2 DIMM of 240 pin DIMM of DDR2-800 unbuffered non ECC memory.
MCP73 comes with integrated DX9 graphics with SM3.0. The HDMI supports up to 1600x1200 @60Hz with multi channel audio.
The other features include 1394, 7.1 HD audio, HDMI Ready header (SPDIF header). The board come with SoftMenu for easy overclockng.