With Twitter's acquisition of Summize, the social messaging service now provides a very nice, and simple to use interface to see what people are twitting about. Enter a topic or keyword and click search. The options in the sidebar of the results screen are substantial too: Feeds, translations, trends, interesting queries, e.g. hashtags. Advanced search and using search operators adds a powerful, Google-like experience to your search.

1. Simple search screen.
2. Search Results. In the sidebar: Feeds, translations, trends, interesting queries, e.g. hashtags.
3. Search operators.
4. Advanced search.

http://search.twitter.com/