To install the BlackBerry Client over the air
Go to this address using your BlackBerry Browser. You'll see a link for downloading the BlackBerry Client. If you see this page again instead of the link, verify that you are using the BlackBerry Browser, and that the BlackBerry Browser Identification is set to BlackBerry. For instructions on checking and setting your BlackBerry Browser Identification, see your BlackBerry help.
Other ways to install the BlackBerry Client
To install the BlackBerry Client using the BlackBerry Desktop Manager, follow this link:
Download FirstClass Mobile Client for BlackBerry
If you want your IT support to automatically push the BlackBerry Client to your device using BlackBerry Enterprise Server, ask them to go to this address and follow this link:
Download FirstClass Mobile Client for BES Push