What ROM are you running?
I would say that the safest way is do a Nandroid backup of your current ROM and setup, then flash Calkulin's EViO 2 ROM that creates a folder on your SD card called "Removed_Apps." It will be in there.
Then, you can just do a Nandroid restore of your current setup and use a file manager to browse the SD card and install it from there (you will need to have the non-market sources box checked in your application settings).
You could do a Google search for the APK, but that could have malware in it and that way you will have access to other Sprint apps that may have been removed from your current ROM.