Noticed a post on Analyzing Twitter Usage on FleetStreet PR Blog that looked interesting, so I tried it, and actually, I liked the charts more than other services I've seen that report on Twitter - but that's just my opinion.  Here's what Twitter Stats looks like:

Twitter Stats

This is a totally ugly engine to produce some stats from your Twitter feed and present them with the Google Charts API, including Tweets per hour of the day, total Tweets per day/month, top @replies and top overall @s.

The code was adapted from http://dcortesi.com/2007/12/27/twitter-stats/. None of your Tweets or other data is stored on the server once the statistics are produced.

Note: Once you enter your username below and click submit, it can take several minutes to produce your statistics, especially if you have a large timeline. Please be patient.

If you have a protected timeline, you will have to temporarorly unprotect it for this to work.

Update: Twitter Stats now has a Google Code page.

Lovingly made by @bck

 —- Tweets per Hour —-
—- Tweets per Day —-