TinyUmbrella Now Supports Verizon iPhone 4
Backing up your SHSH blobs is an important part of Jailbreaking. Luckily Cydia does most of the work, but for those that like to really keep a hold on things, TinyUmbrella is your ultimate SHSH manager. By backing up your SHSH blobs yourself, you can rest assured that you'll be able to get back to that particular version of firmware.
The app works for the iPhone (all versions), iPod Touch, iPad and Apple TV without the need to have your device jailbroken. The newest version, 4.21.08, which is still a beta, supports the iPhone 4 on Verizon.
Knowing this is a Beta and that the developer of TinyUmbrella doesnt yet have a Verizon iPhone, there will definitely be more updates to come. Keep an eye on their website.
The Firmware Umbrella - TinyUmbrella
An alternative to TinyUmbrella is iSHSHit. Check it out while your here.