Anyone know how to make a virtual reality 3d?

dear members,

well i got a question remember on that movie where they took a computer and made that hologram (3d person) and well they could ask it questions and it would do whatever they needed for example i wanted a area on my site where if they went to search a person would pop up on screen and well all the customer would have to do is type in a keyword or well something and the person on the screen would be interactive with them and either pull out a tab or something for the customer to click on or something cool. You probably think i have seen to much SCI-FI channel or Star Trek..

but if someone has an idea on what i am talking about please let me know if that would be very expensive to create or make on a website. i think someone called it VOIP or something to that effect...