You can change your email address via your account page under the "Manage email" link. The site allows you to tie several email addresses to your account, but emails will only ever be sent to your "Primary" email address.
First, add a new email address, and you will be sent an email to verify the address. Once the address is verified, you can set that new address to be your primary one, and remove the old one.
If you run into any issues with this, we can also handle it for you if you send us an email at [email protected].