Screen-shot / Screen-capture Example Please

[Tony Freeman <tony freeman insightbb com>]

I'm not all that great with C / glib programming yet ... but I'd like to
eventually write a useful program for gnome ... and thus teach myself
how to program in C/gtk/glib/etc.  One such program would be something
along the lines of "Lotus ScreenCam".  It's a program that records
everything that happens on the screen/display as well as records voice
input which is then packed together as a movie.  

The first thing I want to tackle is the movie part of the application.
In order to make the movie I'll need some way to capture 23 screenshots
per second.  I'll eventually be looking at the SDL library and others,
but I was just wondering if there is a GTK way to take a screenshot.
Could someone please point me to the proper documentation and/or related
functions that I need to investigate?

Thanks :-)

-- Tony