MyTwitter is a simple integration that allows you to bring your tweets into your WordPress blog. It can be a function to bring them right into your postings, or a widget for the sidebar.
Includes customization options including number of recent twitters to display, formatting options, and stylesheets. It can be called as a function or used as a widget.
The styling allows changes to the CSS and some basic formatting. While there was no screenshots available on the plug-in page, it is being downloaded just under 100 times per day right now.