From My eBay page select the account tab then personal info.
To the right of Registered email address select edit and follow the prompts.
Keep in mind only one eBay account can be associated with an email address.
And you will need to change the payment email address for PayPal if selling as the eBay system will automatically have the old as a template. You will need to double check for a while every time you list an item on eBay.
