If you want to transfer a GoDaddy domain name from one of your account to another your Godaddy account, this tutorial will help you to do it. It's called an Account Change. Also if you want to sell your domain name to another GoDaddy customer, steps are same to this tutorial.
For example, consider your 2 GoDaddy accounts as G1 and G2. Domain name you want to move is http://www.mydomain.com/. You want move this domain from G1 GoDaddy account to G2 GoDaddy account.
1. Log in to your G1 GoDaddy Account Manager.
2. In the My Products section, click Domain Manager.
3. Select/Click on the domain name you want to move.
4. In next page, Click on Account Change.
5. In New registrant's Customer ID or login name, enter the new registrant's account information and click "Next".
6. Now Read the "Domain Name Change of Registrant Agreement" and, if you agree to the terms, select "I have read and agree to the Domain Name Change..."
If you want to transfer your domain name during the 60-day period, you should decline the Change of Registrant and transfer your domain name before updating the Organization, First name, or Last name fields. Otherwise, select "I understand that, if I want to transfer this domain...."
7. Click "Finish".
8. Click "OK".
Wait 20-30 minutes. GoDaddy will email informing you,there's a pending domain name move for your G2 GoDaddy account.
9. Log in to your G2 GoDaddy Account Manager.
10. In the My Account section on the left panel, click "Pending Account Changes."
11. Click on "Incoming Account Changes."
12. Check the domains that you agree to change and then click "Quick Accept"
13. Accept the agreements and click "OK."
The domains will be processed and should appear in your G2 GoDaddy account shortly.