Google Code Search is now live. It is very straight forward, and does exactly what it says -- searches code. I was hoping it would search language documentation too, but that's not the case.
If you are familiar with regular expressions, you can use these powerful strings to get some very specific code examples. What you are searching comes from a huge variety of sources -- any code that Google could find, it indexed. That includes files found in compressed and archive files scattered around the internet.
The results are a bit ugly, and I don't know how useful it will be -- but when I need answers to a coding problem, I'll give it a shot. For complete details visit the FAQ.