For registration Go to Google Code In. If you are not able to register read below.
Registration process for Google Code in.
1. Click Register.
2. Log in with your Google Account
3. Enter Your Date of Birth.
4. Enter All the details.
5. Read all Terms and conditions.
6. Copy the parental link and open it in new tab.
7. Fill all the details.
8. You are all set. You will get an email open this. And Goto Dashboard.