Pop-up text boxes?

[mike_heroys]

I'm assembling a presentation to help teach reading in a primary school. I'd like the teacher to be able to click on a word in the text which displays a pop-up box explaining what it means.

e.g. click on "Britain" and it displays a pop-up box saying "a country in Europe".

Ideally the text in the pop-up could be formatted with a different font, bold, italics etc.

I can't work out a way to do this in PPT that doesn't involve creating a separate slide for each definition ( nightmare!). Any ideas, anyone?

I'm using ppt2000 on Win XP.

Thanks.