The first and most important thing about sharing the boss's vision with employees is that the boss actually has to have a clear and concise statement of that vision. That may sound like a given, but I can assure you that it's not.
When I deal with a business client for the first time, I ask them what their vision of the future is. Most really don't have one, they ramble on without saying much that's relevant. The ones that do have a vision usually haven't developed a simple version that they can share.
I suggest the Intelligent 15-Year-Old Test. Find any fifteen year old. The only requirement is that he or she not know anything about your business. Tell the teenager your vision for the business. Then ask them what you said. The results can be startling.
Once we've got a short, memorable statement of the vision. we need to communicate it as content. Pour the vision into any medium you use. Consider email, the web site, paycheck stubs, the office bulletin board, chalk drawings, tattoos, stained-glass windows -- anything.
Then communicate it at every opportunity. Years ago, John Kotter's study of general managers found that the successful ones were always on the lookout for a chance to share their key message.
Remember that you will get sick of the vision statement long before your people will have internalized it. You should be using the same vision statement with the same frequency for years.
Make sure your internal systems align with your vision. If customer service is important, praise folks who provide it. Promote them. Pay them more. Do all this publicly.
And make sure that your direct supervision and your appraisal process support your vision.
Finally, and most importantly, live it. What you do and say should reinforce the vision at every opportunity. Talk the talk, it's important. But walk the walk, too. It's even more important.