To install GeoMobile on your device, just access to this page from the browser of your mobile device and click the link for the desired version.
For all major device compatible with java.
Version for BlackBerry Storm and recent.
Version for previus BlackBerry.
Alternatively you can download the zip file, containing all versions of the software, on your PC. Then you can choose the most suitable version and upload it on your mobile device with the most advantageous method to you.