I know that there is already a very nice .net class to communicate to Arduino via the Firmata protocol. But!
unfortunately this protocol has no support for the use of character LCD. So i decided to develop my own Sketch and .NET Class so i can create projects involving I/O and LCD.
This is a very EASY TO USE class for beginners and advanced .NET Developers.
The link below will download the Class and Sketch. that is all you need to start using Arduino!
I also included a very nice set of User Controls Switchs you can use in your project.
You can download this controls with the link below. http://www.4shared.com/get/aBcSf5ll/Real_Switches.html
This Class has no support for servo motors YET! that's because i don't have a servo motor. I will add a servo support as soon as i will own one... (Very soon).
The "digital Message Receive" Event Raises on a seperate thread. so if you want to update your form controls inside the event procedure add the line: CheckForIllegalCrossThreadCalls = False at the form Load Event.
The Class Developed for the use of Arduino Duamilanove 328 boards but i guess it will work on other boards too.
The Class supports for a maximum of 13 digital pins.
Using The LCD support requires you to enable the LCD Engine from the sketch file by removing the "//" from the start of the line : // LiquidCrystal lcd(lcdRS,lcdEN,lcdDB11,lcdDB12,lcdDB13,lcdDB14);
Also change the Pin Number Constants in the sketch according to your project.