It's great. I just tried it on my Palm Treo 650 PDA.
If you look at it on your desktop PC, you'll get an introduction to google mobile maps. But if you look at www.google.com/gmm on your cell phone or cell phone PDA, you'll be prompted to download the executable program. You'll need to install it to run. You will need an active internet connection to use this, so if you don't have a smartphone or PDA phone with internet access, you're out of luck.
But you who live on dreams, you are better pleased with the sophistical
reasoning and frauds of talkers about great and uncertain matters than
those who speak of certain and natural matters, not of such lofty nature.
-- Leonardo Da Vinci, "The Codex on the Flight of Birds"