Bing Webmaster Tools links to a Bing search for "How to add CNAME record to GoDaddy.com" that doesn't explain it clearly. You need to add a CNAME record to verify your web site for Bing Webmaster Tools using the code provided when you add your site. It's easy. Here's how:
1. Add the site in Bing Webmaster Tools
2. Scroll to the bottom of the Verify Site Ownership page. The unique alphanumeric code is provided.
3. Login to your GoDaddy account where your domain is hosted.
4. Under the Domains menu, choose Domain Management.
5. Choose the domain you want to create the CNAME (Alias) record.
6. Click the Launch link under the DNS Manager section.
7. At the bottom of the CNAME (Alias) section, click the Quick Add link.
8. In the Host box, enter the alphanumeric value provided by Bing.
9. In the "Points To" box, enter: verify.bing.com
10. Click the "Save Zone File" button in the upper right area of the page.
GoDaddy indicates that the change can take up 48 hours. The change took effect in less than an hour for me. You can test this yourself. Once the Domain Record is updated, alphanumeric.yoursite.com should point to www.bing.com When the redirect works, you can login to Bing Webmaster Tools and verify your site.
Please let me know if you have any issues.