Before you can boldly go and roll your design out across the entire enterprise, you need to run a pilot implementation. Your pilot implementation should consist of a very small-scale deployment that represents the design as a whole. Try to identify a sample of your enterprise user population that takes advantage of as many of the features and functions of your design as possible. This sample should be around 20 people. Try to find 20 people who can put to the test as much of what you're deploying as possible, including such things as the following features:
New security features
Your list will vary from the one above, depending on which Windows 2000 features you'll be deploying, but the idea is to get a feel for how well your new architecture will work across the enterprisewithout taking the risk of deploying it in its entirety across the enterprise. If you can work with a small and easily manageable group of systems and still get a feel for how all of your design will work, you'll gain the most benefit from your pilot implementation.
If your pilot implementation uncovers unexpected problems or failures, you'll need to change your design plans accordingly and get back to the test lab. If your pilot implementation goes as expected, however, there's still another step to take before an enterprise-wide rollout.
Whether your pilot was successful or not, you should hold a "Lessons Learned" session. Sit down with key members of your implementation group and examine the pilot implementation. Note all the elements of your deployment plan that were successful and look for reasons why. Then examine any elements of the plan that were not successful, and determine why not. Can any of the failed elements be adapted or modeled after those that succeeded? Can any of the successful elements be streamlined or made more efficient? Answering questions like these can help you to develop the most effective deployment plan possible.
If your first pilot was unsuccessful, hold another one after you have analyzed and amended your design. Once you have a successful pilot, get the participants of that pilot to spread the word about the success of the new architecture. This way, the rest of your users will accept and even look forward to your future deployment.