MLB.com's tech support replied and told me that they were having site issues earlier. Looks like we're OK now if anyone want to try again. See the 1st post for the link.
From linked page click on Free Sign Up Now
Click on Create a new team
On next page, enter a team name and click on Private in League Type
Click Join Private league
Enter 8879 in League ID and whatif in password
Click Submit.
See you there.