If you can use perl regular expressions then you can use grep. It's not fancy, but it's powerful and fairly easy. I think any other fancy tool you use will just complicate things.
To search your project source files just

 $ cd /project/dir
 $ grep -R 'some_regex_to_look_for' -i .
[download]

This will look recursively and case insensitively. I can't think of a better way to get more bang for your buck.