Yes you can. The two programs merged together on October 1, 2009. You should expect an email from Skymiles when your accounts have been fully consolidated if you had previously linked them together. Your WorldPerks number will be replaced with a Skymiles number. All miles earned and status will be transferred to your new Skymiles account. All the program details and changes can be found here:
https://www.delta.com/skymiles/about_skymiles/what_to_expect/worldperk s.jsp
