Unique visit counter

Hello guys,

I'm looking to install a counter on a webpage; one that registers unique visits to the site, as opposed to pageviews.

This is with the purpose of knowing how many different people visits the site, and not only how many times a given page has been viewed (which is what my actual counter does).

Do any of you know where to find the code for this type of counter?

Thanks in advance.

Cheers!