I've tried projecting from a 17' i book but it doesn't seem to work all i get is the desktop and none of the icons/dock.
I've tried altering the resolution but this didn't work either. What am I doing wrong?
You need to turn on display mirroring. This can be done by pressing the F7 key, choosing "Turn On Mirroring" from the display menu, or clicking on the "Mirror Displays" checkbox in the Arrangement tab in the Displays preferences. Just hitting F7 is the fastest, though.
By default, when you plug in a new display, it essentially continues the desktop to the right side of your main screen. So, if you move your cursor all the way to the right, it will show up on your projector. This is very useful if you are working in an environment where more screen space is necessary, such as video editing or graphic design, or you need to see extra information on your main screen while running a presentation on the other screen. Keynote offers this functionality, displaying upcoming slides, time elapsed, and notes on your main screen while running the slideshow on the second screen (that's connected to the projector).
Hope that helps -- let me know if you have more questions. I have a 15" PowerBook that I use for running presentations and video on a regular basis.
-Ryan