Glad to see this! As a connection for Mac & Linux users who have a bash shell handy, I wrote a script that does the same thing:

Script: Download OTA app to install from SD card

Besides making backups of the OTA stuff, these tools are really handy for downloading large OTA using your PC then installing from the SD card (maybe you don't have a data plan, or pay $$$ per kb downloaded on the BB). All sorts of nifty uses.