Yes it can be done wirelessly. You need to use the blackberry handheld configuration tool.
copy the install files to a shared folder on the server.
Open the handheld configuration tool from Start > Programs > Blackberry Enterprize server
run loader.exe /index
click on Software configuration on the left hand side
From the tasks on the right add new configuration
Call the software RSA or whatever
Browse to the folder share.
next and finish.
(its the loader.exe /index which throws people) if this is not done you cannot add the application
You could also do a search
I just found this Wireless Application Push