Note: You need Mac OS X Leopard and Numbers to do this.
Download the Twitter stats zip at http://dcortesi.com/2007/12/27/twitter-stats/.
Put the folder on your desktop and ensure it is named twitter_stats.
Open a new terminal window.
cd Desktop/twitter_stats, hit enter. You've navigated to the Twitter stats folder now.
Enter the following command:
perl twitter_stats.pl twitter_username tweets.csv. Replace twitter_username with your own username.
Follow the instructions onscreen. First, hit enter to start generating the CSV file which contains your stats. When this is done, you will get the following message: "Tweets per hour, data has been copied to the clipboard."
Open the numbers template in the twitter_stats folder. And paste paste the data in the topleft yellow table cell.
Repeat the process for the 5 tables in the numbers template (pasting the data in the correct tables), hitting enter inside terminal to get the new data on your clipboard.
Now click "Sheet 2″ in the Numbers template and you'll see your stats.
The results will look like this: