It doesn't matter. An OS is an OS, as long as it matches your hardware. A Sprint OS for the 8130 will work perfectly on a Verizon 8130. We only sticky one version, not one for each carrier. You can check Verizon here: Verizon BlackBerry Software Updates.
Everything will be deleted, but everything usually can be restored. Sometimes 3rd party apps have to be reinstalled. But for the most part, you back everything up, then restore from the backup after the OS upgrade. The "Upgrade / Downgrade Procedure" that's linked in my signature is a reliable guide, with one exception. It was created before BlackBerry Swiss Army Knife was created, so it doesn't refer to BBSAK. BBSAK is probably the best way to backup and restore your 3rd party apps.
Go slowly, and don't do a step if you don't understand it. Upgrading an OS is not difficult, but it is not trivial either, and sometimes the process goes awry, no matter how experienced you are.
