Click on My eBay at the top of the page and select the Account tab. On the left under My Account choose Personal Information. Find Email and Contact Information, and on the right you will see the word Edit.
If you've "been hacked", you may also wish to change over in your paypal account. Go to www.paypal.com and log in, then choose Profile. Click the Add or Edit email link, -- out with the old and in with the new.
Might be a good idea to change your passwords while you're at it.
