People have done all sorts of interesting things with Google maps, but this one I particularly like. Maplib lets you upload any image (the larger and higher res the better) into the Google map interface, turning the picture into a draggable, zoomable and annotatable terrain — a crude mashup tool that nonetheless suggests new spacial ways of navigating text.
I did a quick and dirty image mapping of W.H. Auden’s “Musee des Beaux Arts” onto Breughel’s “Landscape with the Fall of Icarus,” casting the shepherd as poet. Click the markers and then the details links to read the poem (hint: start with the shepherd).

As you can see, they give you the code to embed image maps on other sites. You can post comments on the individual markers right here on if:book, or if you go to the Maplib site itself you can add your own markers.
I quite like this one that someone uploaded of a southerly view of the Italian peninsula (unfortunately it seems to start larger images off-center):

And here’s an annotated Korean barbecue (yum):