The following is from memory so I may have made errors. Please correct me if I made a mistake.
Step 1: go to cakewalk.com and navigate to the forums.
Step 2: Click "Log In" at the top right of the page
Step 3: click the "I have a login" button and ignore the "Existing Users" field boxes (this is for people who have already done the migration I think)
Step 4: Fill in the appropriate info *NOTE: even if it says "email doesn't match" but you know the email is correct just type it into both boxes (email/confirm email) and continue on
Step 5: After submitting the info it will ask you to confirm the account so log into the email account you provided and click the link
Step 6: Throw a hamster on the barbie and call it a day
Alternate Step 6: Correct Beepster's instructions above and he will edit his post.
Edit 1 from scook (this probably only happens if your store account is linked to your forum email/username... someone else can verify):
My step 6 was verify the product list. The "my-account" Products list was populated for me. The product list is in approximately the same order as the old store account. There were some product name changes and a few older items missing. Peace.