What is TwitThis?
TwitThis is an easy way for people to send Twitter messages about your blog post or website. When visitors to your website click on the TwitThis button or link, it takes the URL of the webpage and creates a shorter URL using TinyURL. Then visitors can send this shortened URL and a description of the web page to all of their friends on Twitter. Add the code to your website, or download the wordpress plugin (both @ http://twitthis.com) for your blog/site.
Update: Tues 30th September, 2008
Seems the site is having a little trouble right now.. out of disk space or something.. *weep*