I was rather surprised to find that Google Latitude works great on the Prē if and only if you know this magic invocation:
Why the hell doesn't http://google.com/latitude mention this? It's a mystery.
If you plug in the magic invocation, it pops open your Google Maps application in Latitude mode. I bookmarked it. I would guess there's a way to start up the Google Maps application in Latitude mode directly, but I can't figure it out.