There are plenty of resources online that explain how to access iSight:
This article explains how to use QuartzComposer for capturing images with iSight. The benefit of using QuartzComposer is that you don't have to write a lot of code to capture an image. All you have to do is setup a QCView with IB and bind it to an outlet, then to get the snapshot you call this method:
NSImage *screenshot = [isightView snapshotImage];
Alternatively, you could also use:
- (id) createSnapshotImageOfType:(NSString*)type
The code in the article didn't work for me:
NSImage *currentImage = [qcView valueForOutputKey:@"ImageOutput"];
The article also forgot to mention that you have to import and link to the following frameworks:
#import <QuartzCore/QuartzCore.h> #import <Quartz/Quartz.h>
Haven't tried this one yet.
This example is not complete.
Have a look at one of the demos like StillMotion