Can I use Google as a search engine for my site?

I see some sites have search functions “powered by Google”. Is there a simple code I can add onto my site to enable visitors to search by keyword in a directory of my site?

This might help.
http://www.google.com/faq_freewebsearch.html#site1

There was a front page is either wednesday’s or thursday’s USA Today about that exact topic, how to make your web site Google friendly.

USA Today

USA Today?!

Does the article come with a colorful pie chart?

Because I don’t read anything without pie charts.