It seems like Apple just released a new iOS firmware for the Verizon iPhone. The iOS version is 4.2.6 and it's available for direct download here. Apple apparently did some subtle tweaks to the operating system for the CDMA iPhone, which was running iOS 4.2.5 at the Verizon media event where the iPhone was officially announced. iOS 4.2.6 is a modification to the original 4.2 OS that can run on Verizon's CDMA network, and includes the Personal Hotspot feature that allows users to turn their devices into mobile hotspots capable of sharing a 3G connection with nearby phones.
The firmware posted online is for the "iPhone 3,3", which is the model name of the Verizon unit. It's a 642 MB download, build number 8E200.
Rumor has it Apple sent out review units to selected journalists and bloggers earlier today, and that's probably why the firmware has been posted online.