We have 16 server admins and about 100 servers.  Do we need to buy the licenses for the servers or the admins?  In otherwords, do we buy 16 or 100?

When the license expires in a year, does that just stop you from upgrading or does it also stop you from using the application?

The licensing is a bit confusing, but from what I've learned, you'll have to buy a license for each admin, so 16 licenses in this case. The "Single User 10 users" are price breaks...if you buy 10 or more licenses, you pay the $88.94 for each instead of $98.94 for each license. They don't charge you for the end-users/clients, just for the users that will be using VNC Manager.

Also, I believe the license is for the lifetime of the program, the 1 year expiration is for support and free upgrades.

As Max said you only need 10 licenses. He is also right about license expiration. Once purchased, the license is never expires. But after one year since purchase you won't be able to use new builds of VNC Manager.

Does this mean that if I buy the current version, we will be eligible for version 3 whenit comes out?

What is the ETA for this version?

Also, will this defaintely scan for RDP (terminal) servers?

Yes you will be able to upgrade to 3.0 for free. At the moment v3.0 is scheduled for release by the end of March or first part of April.
And yes, it will include RDP scan, as well as support for RDP servers in dynamic search folders.

Dynamic search folders is a new feature,  which will allow to create a folder in the tree and set it to show active RDP or VNC servers found in user specified IP Range or domain. This is pretty much the same as old VNC servers scan, but more powerful.