Hi I've been working on a .Net library to control an arduino Mega (Will make a version compatible with other arduinos soon) through USB ! I originaly made it to control my CNC but I though some people here might be interrested
The library is entirly written in C#. You just have to import the Dll into you .Net project, flash the program the the arduino and you're done ! I've included a demo software with the library so you can see how it works
With this library, you have total control of the arduino though the software, it can do:
Add SPI support
Add i2c Support
Make version compatible with Uno/Duemilanove/Diecimila/Mini etc...
You can find it here:
Have a nice day