a friend [thanks martin] put me onto prezi, an online presentation piece of software. it's easier to see than explain so just go and have a look at their samples. you basically create a big map or flow chart of your presentation that you can add images and text to and group into frames. then follow the path in a linear way or click on any image or text to zoom in on that at any point. and whenever you like zoom back out to see the big picture…

i have put together one so we'll see what people think when i use it – i'll let you know in the comments next week! it makes a change anyway from keynote or powerpoint. like all these things the free version has limited storage and options but you can buy a version fairly cheaply. i'm sticking with free. it was very intuitive and easy to use.