Yeah, this is posted a dozen times on various boards but still, this is the easiest way I've seen to get Google Maps up and running on the Treo 700wx.
1) download and install J9 app in attachment
2) go to
http://google.com/gmm in PIE
3) Select High End phone and install
Now just run the J9 app and run Google Maps!
I have to admit...this setup with the softkey support (no touch screen) works very, very well on this device.
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After playing around a bit, I decided the freeware application
Map4PDA is much more robust, easy to use and better program than just google maps (this has gmaps built in as well), so I suggest using that over the above. Get it here (you'll need CF 2.0):
http://map4pda.com/download.1.4.htm