Just in case you haven't already seen it, there is a number of new .NET MicroFramework 4.1 devices in town, 3 to be exact, - the "Netduino".
The company Secret Labs have made these nice boards of which 2 are Arduino hardware compatible (it can use many of the same "Arduino shields" (plugin interface boards) - some may need minor modifications to the signal levels!) and one is "Basic Stamp 2" compatible..
The Netduino comes in several flavours - all based on the same Atmel 32-bit ARM7 chip AT91SAM7X512 - Standard, Plus and Mini.
I have grabbed some product pictures from the Secret Labs homepage (left to right: Standard, Plus):
The Mini is only 0.6"x1.2" (~15mmx30mm) in size. It plugs directly into a breadboard, as the pins are spaced on a 0.1" standard grid:
As of the date of writing this, only the Netduino standard board is available for purchase, but the other 2 will also be available soon, according to Secret Labs.
Like the Arduino concept, the Netduino is also Open Source. This means that you can get hardware schematics, board design files and software and reuse it for your own purpose :-)
Standard and Plus are Arduino pin compatible development boards, where the Mini is like a "24-pin DIP chip" you can use in your own hardware designs. The Mini is "Basic Stamp 2" pin compatible (from the company Parallax).
The Netduino Plus, has built-in ethernet connector.
I personally find the Netduino Mini to be the most exiting of them all.
I bought one of the "standard" editions. It is priced nicely at US$34.95. My experience with it is that it just worked when plugged in to the PC. It has good performance and enough of memory too.
One thing I noticed which I especially like, is that the USB interface is fast and reliable, unlike some of the other boards from other vendors I also have experience with!
Technical specifications for the Netduinos can be found here:
Netduino Standard specifications
Netduino Plus specifications
Netduino Mini specifications
Thumbs up and welcome to the new inhabitants in the .NET MicroFramework world.