libvcvideo is targeted as a super-simple cross platform video device library. It's starting with the most basic features and building up, all while keeping a simple API and strong documentation for beginners. Currently only select devices are supported, but as more hardware becomes available that will change. Right now it only has limited compatibility with Linux Webcam devices that use the original V4L specifications and output RGB24 data. This is actually a very large set of devices, as that is the generic description for most spca5xx and gspca devices. Though incomplete, if you have the right device it is very simple. Counting variable declaration, you only need four lines of library code to get a frame from a camera.
TclScreenUP is a little utility that grabs a screenshot, allowing you to set a delay prior to grabbing the shot. It also allows you to set the dimensions of the shot, shows a preview, uploads it to your Web server, then displays the URL. It allows you to save profiles with your server information, preferred browser, etc. You can have multiple profiles.
SDL_bgrab is an SDL conversion of the libbgrab framegrabber library. It uses a separate thread to grab images into a framebuffer independent of an external "game loop" to make it easy to integrate live video into other applications. Images are grabbed at 32bit RGBx resolutions, and several deinterlace algorithms are available to improve image quality.