[pc]

There's quite a few of them:

http://web.analytics.yahoo.com/
http://www.haveamint.com/
http://www.sitemeter.com/
http://www.histats.com/
http://www.getclicky.com/
and
http://www.google.com/analytics/

I use google analytics but read that Yahoo analytics is way better, didn't try it though.