Go to the following link from your handheld or PC
www.blackberry.com/maps
If the above link does not work over the air or through AXLoader, please run through it, accept all of the terms and conditions, etc., and then click on the link below:
www.knology.net/~acidmax/blackberry/maps.jad
I'm not sure if there is a different one for the 8700 and 7100 device forms, but it doesn't appear that there is (but maybe so). Please just be sure to go through and accept all of the terms/conditions and disclaimers and whatever else RIM has carefully worded. This is important to them, obviously.
And this appears to be the portal page that may or may not be launched (this week?):
maps.blackberry.com