Google launches Google Code Search

Google has launched yet another Developer friendly service yesterday ie Google CodeSearch(http://www.google.com/codesearch).
It's a search engine developed for developers and it provides an interface to use RegEx to search code snippets they are looking for. I didn't try it much as now I am headed to some other things... I felt it will be extremely useful to you people.
Google Code Search helps you find function definitions and sample code by giving you one place to search publicly accessible source code hosted on the Internet. With Google Code Search, you can:
- Use regular expressions to search more precisely
- Restrict your search by language, license or filename
- View the source file with links back to the entire package and the webpage where it came from