Here's how to create a "non-Korean" or "non-Resident" DAUM account. First go to www.daum.net. (Click on the image to see the full size version.)
Then you'll have a pop-up message that reads "The confirmation number was sent to your email you had just entered." Now you need to go to your email (Make sure NOT to close your registration page as you'll have to come back there within 5 minutes.). Now, open the mail from DAUM. Then there you see six digit confirmation number, e.g. 인증번호: 123456
When you go back to the registration page, you'll find a new blank spot right below the spots for your email address that needs filling in. There you enter your confirmation number and click on the button that reads 인증하기.
Lastly, to prevent robot-triggered submissions, you have to enter the case letters and numbers in the image code below into the security text field. That'll complete your signing up process.
Note that DAUM wouldn't accept the same email account more than once. In case you fail to get to use your confirmation number within 5 minutes but still want to create a DAUM account, you'll have to provide them with a different email from last time you registered. Good luck!