Michał Surowiecki

If u want to hide a website from google search engine to don't display the site in the search results just:

add this tag into your website:
<meta name="googlebot" content="noindex">

or:

<meta name="robots" content="noindex">

if u want to hide the site from all search engines (yahoo, bing...).

http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=93710&from=61050&rd=1