Verizon's data packages for smart phones are still unlimited. I've used 10+ gigs before and never heard a peep out of them.
I also tether with my Droid-X without paying the additional fee (root ftw) and they've yet to give me grief for that either. Mind you, I'm extremely careful about what I do when tethering. Mostly use it for lightweight web browsing and VPN into work. If you start streaming video and running bittorrents on it I'd wager that they'd be less than pleased with you.....
That's good that you have unlimited data with Verizon. I had heard that Verizon's 'unlimited' wasn't. I switched from AT&T's miserable 2GB plan to Sprint's unlimited. So far, 3 weeks in and I have used 3.2GB. I have no worries about what I use. On at&t, I used to check every day to make sure I wasn't using too much.