Google analytics was launched several months ago, but after some experienced teething problems I avoided it, but now however, there are several wordpress plugins which can be used to utilise the google analytics code
The analytics program from google is free (along with their other webmaster tools) and it allows very detailed analysis of the traffic on your website.
For churches, it makes it easy to see what pages visitors look at first and at what point they leave the website. This could be useful in re-designing pages to be more visitor friendly and avoid pages way visitors get stuck and give up.
What surprised me, was the level of detail that the reports contain, placing visitors to towns, not just countries. If you have not tried it, it is worth looking into.