Yes, it will be an OTA update as soon as Google releases the open source and Verizon sends it our way. There are many threads about this, so please use the search function next time.
Well a lot of people are now saying it's going to come in a few days. Which i'm a little skeptical about since they only said that it would go Open source in a few days. I think the Jan 22 date is more likely as I think optimization for the droid's hardware is needed. But I'm no expert so it's just my opinion.