I’ve just been playing with Google Documents slideshow tool. On the whole, very impressive.
Positive points include the ability to share and chat online, allowing you to present remotely and only have to worry about voice connectivity.
Negative points include (and this might be my stupidity) a complete inability to figure out how to use the text formatting controls. No matter what I did I couldn’t change the size of my text, even though the font-size control was right before my eyes, taunting me.
If anyone finds it useful, fair play.