If u want a theme, then u can download it over the air, meaning from the internet to ur Blackberry, or u can download the theme "zip file" to ur computer and then hook up ur Blackberry to the computer and install the theme that way.
Go here to find the zip files and the OTA downloads:
http://www.forum.eveek.com/downloads/
And yes u need to have a data plan (internet package) to download OTA (over the air) so if u dont have that then ur only option is to do it via computer+usb cable
