Right now Verizon has three 4G LTE devices; the HTC Thunderbolt, Samsung Droid Charge, and the LG Revolution. One thing they all have in common is that they have a full size SIM card, and it looks like they will be the only devices to ever be compatible with the larger cards.
The Samsung Galaxy Tab 10.1 LTE version is on the way, and it has been confirmed that it will be the first Verizon LTE device to support a micro SIM card.
At first, the thought was that Verizon was doing this to make sure you are not able to change out cards between devices, but it looks like they are going to be adopting the micro SIM cards moving forward.
For the Thunderbolt, Charge, and Revolution owners, the micro SIM card will fit into your phones, but it will not work. We will have to wait and see what the Droid Bionic shows up with early next month when it launches.