Update (11:44:58 AM EDT): This site seems to be back up and online!
Someone has hacked together an app which will bring Google Maps to your Blackberry handheld device. From the app's website:
HelloWorld is a Blackberry application that brings Google Maps to your Blackberry.
You need a Blackberry with OS 4.0 installed.
How do you get it?
Go to www.freek.ca/HelloWorld.jad with your Blackberry and that should start Over-the-Air (OTA) installation.
More information about the application is located on this website.
Little known fact: both the RIM Blackberry and Google Maps Mania are both produced in the same city!