Google maps is one of my favorite apps on my blackberry smartphone, it provides satellite, traffic, terrain views. You can search the map for popular places, get driving and walking directions with estimated time of arrival.
Google maps app has what it calls LATITUDE which makes it possible to connect with friends with gmail account. Apart from the fact that you get to see as much as the roof of the house you or friends are in (if you guys are indoors), you can 'ask' the app to 'show you the way' to each other. I ve had to use this to locate a colleague working on a remote site without having to ask strangers for directions.
So go ahead and download google maps asap 'cos you never know when you might need to find your way back home :-).
Go to m.google.com/map with your smartphone's browser to install.