Add contribution instructions.

CONTRIBUTING.md

@@ -0,0 +1,24 @@
+Want to contribute? Great! First, read this page (including the small print at the end).
+
+### Before you contribute
+Before we can use your code, you must sign the
+[Google Individual Contributor License Agreement](https://developers.google.com/open-source/cla/individual?csw=1)
+(CLA), which you can do online. The CLA is necessary mainly because you own the
+copyright to your changes, even after your contribution becomes part of our
+codebase, so we need your permission to use and distribute your code. We also
+need to be sure of various other things—for instance that you'll tell us if you
+know that your code infringes on other people's patents. You don't have to sign
+the CLA until after you've submitted your code for review and a member has
+approved it, but you must do it before we can put your code into our codebase.
+Before you start working on a larger contribution, you should get in touch with
+us first through the issue tracker with your idea so that we can help out and
+possibly guide you. Coordinating up front makes it much easier to avoid
+frustration later on.
+
+### Code reviews
+All submissions, including submissions by project members, require review. We
+use Github pull requests for this purpose.
+
+### The small print
+Contributions made by corporations are covered by a different agreement than
+the one above, the Software Grant and Corporate Contributor License Agreement.

README.md

@@ -1,14 +1,15 @@
-ReCAPTCHA
-=========
-URL: https://github.com/google/ReCAPTCHA
-Version:
-License: BSD
-License File: LICENSE
-
-Description:
+# ReCAPTCHA #
+
+* URL: https://github.com/google/ReCAPTCHA
+* Version:
+* License: BSD
+* License File: [LICENSE](https://github.com/google/ReCAPTCHA/blob/master/LICENSE)
+
+## Description ##
 ReCAPTCHA is a free CAPTCHA service that protect websites from spam and abuse.
 This is Google authored code that provides plugins for third-party integration
 with ReCAPTCHA.
 
-Local Modifications:
-None.
+## Contributing ##
+
+We accept contributions via Github Pull Requests, but all contributors need to be covered by the standard Google Contributor License Agreement. You can find instructions for this in https://github.com/google/ReCAPTCHA/blob/master/CONTRIBUTING.md