OpenCV 2.0 can be difficult to setup and install. Here are some setup instructions for Windows and Mac OS X, including how to create a new project in Visual C / Xcode.

Windows Setup

Firstly, we need to compile OpenCV for Windows. You can download OpenCV from the SorceForge downloads page.. Get the latest version (as of writing, OpenCV-2.0.0a-win32.exe). You will also need a copy of CMake, so download and install that too.

Run CMake GUI tool and configure OpenCV there:

Click the Configure button in the lower left hand corner, and in the window that opens, choose your IDE (e.g. Visual Studio 9):

Once you've done this, click configure again, and the generate button should become enabled:

Click the generate button:

Once all the files have been generated, you will need to open the project that has been created in the output directory you choose earlier:

Build this project in both debug and release mode (this could take a bit of time depending on your computer):

When creating a new project, you will need to ensure that the headers and libraries are available:

Add the following to your new project (Tools → Options → Projects and Solutions → VC++ Directories):

Include Files

Add in the directory containing OpenCV header files (e.g. C:\\OpenCV2.0)

Library Files

C:\\[OpenCV2.0 Build Directory]\\lib\\debug

C:\\[OpenCV2.0 Build Directory]\\lib\\release

Source Files

C:\\[OpenCV2.0 Build Directory]\\src\\cv

C:\\[OpenCV2.0 Build Directory]\\src\\cvaux

C:\\[OpenCV2.0 Build Directory]\\src\\cxcore

C:\\[OpenCV2.0 Build Directory]\\src\\highgui

Thanks to Yen-Sheng Pan for these instructions.

Mac OS X 10.6 / Xcode 3.0 Setup

Download and install the package here: OpenCV-2.0.0-Darwin.dmg.

Create a new Xcode "Command Line Tool" project:

From the menu, select Project → Edit Active Target "...". Under the "Configuration" drop down, select "All Configurations", and then edit the options under "Architectures" to match the following:

You should now be able to compile your project with OpenCV.

Simple Example

#include <iostream>
#include <opencv/cv.h>
#include <opencv/highgui.h>

const char * WindowName = "Video 01";

int main (int argc, const char * argv[]) {
	CvCapture * capture = NULL;
	IplImage * frame = NULL, * prevFrame = NULL, * diffFrame = NULL;
	int key = 0;
	
	// Initialize Camera
	capture = cvCaptureFromCAM(0);
	
	if (capture == NULL) {
		perror("Could not open camera device!");
		return 1;
	}
	
	frame = cvQueryFrame(capture);
	prevFrame = cvCloneImage(frame);
	diffFrame = cvCloneImage(frame);
	
	cvNamedWindow(WindowName, CV_WINDOW_AUTOSIZE);
	
	std::cout << "Frame : " << frame->width << ", " << frame->height << std::endl;
	
	while (key != 'q') {
		frame = cvQueryFrame(capture);
		
		if (frame == NULL) {
			perror("Could not get frame from device!");
			break;
		}
		
		cvAbsDiff(frame, prevFrame, diffFrame);
		cvThreshold(diffFrame, diffFrame, 32, 0, CV_THRESH_TOZERO);
		
		cvCopy(frame, prevFrame, NULL);
		
		cvShowImage(WindowName, diffFrame);

		key = cvWaitKey(1);
	}
	
	cvDestroyWindow(WindowName);
	cvReleaseCapture(&capture);

    return 0;
}

Thanks to Björn Giesler for putting together an installer.

OpenCV 2.0 Documentation

The best documentation I can find is this wiki. It has a good search function and I've generally found the documentation to be concise and easy to understand.