Where can I find the API code for use with visual basic?

I’d like to find code examples for reading serial information being transmitted from the Xbee via an ATMEGA328P (stripped down arduino chip). Communications are running fine with the arduino chip, xbee, and x-ctu. things are readable and working, now i need to run an app to gather the data and work with it. Preferably via visual studio using visual basic or c++. Can anyone provide a link to some useful examples? All I have found read values of an analog pin on the xbee.