If you want to develop for Google Chrome extensions, you will be so pleased if you already know JavaScript, the extensions are some sort of JavaScript pages (frames) that interact with a variety of APIs.
The Google Extensions website for developers on Google Code -http://code.google.com/chrome/extensions/getstarted.html- is really amazing (as all the other products explained by Google) and it’s too detailed and simple to follow and start getting your hands on the Chrome extensions.
After a while you will need to try out the examples they provide, and the best way is to checkout their ready-to-run samples using you favorite SVN tool, here I use TortoiseSVN for Windows and it’s working pretty cool.
In your favorite directory, right click in a free space and choose SVN Checkout.
On the next window, choose http://src.chromium.org/svn/trunk/src/chrome/common/extensions/docs/examples/ as the repository URL and there you go.
You get 3 folders : API, extensions and tutorials, inside the api folder you get all the examples of the api exposed by the Google Chrome extensions. The extensions folder contains 6 ready to use extensions which includes Gmail, Mappy, News and more.
This is a simple Twitter feed reader I coded in less than 15 minutes :) http://twitpic.com/t31pp If you created something cool, let me know about it in the comments.