Conservative NZ, the following link is for a forum thread that may be of use: SheetsToGo with Rogers $15 plan
I do not have a data plan, and installed & used the app mentioned, BlackBerry OTA Downloader, over the weekend.
W/it I downloaded the OTA files for Documents To Go (DTG) 1.002, which includes Sheet to Go. I then copied the files to my BB media card and installed DTG from there. Flawless.
You may download BlackBerry OTA Downloader here: Blackberry OTA downloader