is there a way to popup a small 'bubble' or 'balloon' of text when a user lets their pointer rest over a particular part of an image? (an image map)

explorer does this sometime (randomly it seems) when i let my pointer rest of an image that has alt text - it displays the alt text in a speech bubble thing - but only sometimes! so that is no good. also netscape doesn't have this and obviously i want something that'll work in both.

the reason i want to do this is this - i've got a simplyfied map (a geographical map) as a picture. there's a small piece of info i wish to show for each country, but the map is too small to allow me to put the information directly on the map - so i figured popup bubbles would be a good way.

anyone know of anyway of doing this? thanks