Hey - for those who just want to try it PiWik out without installing it. I did a hack to allow users to sign up on my dedicated server. I am still working out the kinks but if you want to try it out - sign up here: http://www.branica.com/piwik/signup/ No hidden links - all free for now . Just an FYI - it is just for testing and I will probably purge the data after a while.
I am sort of testing that out - but don't forget that PiWik is still in beta. The nice aspect of PiWik is its URL API. You can create all kinds of cool reports and analysis with it - very useful.