To update your email address, access the link below to navigate to your profile. From there, select the link on the left to 'Edit Profile'. On the next page expand the Email and Password & Facebook Connect section. There you'll be able to swap at your new email address with the old one.
If you need further help with this, or run into problems, please contact our Customer Service team - either by phone at 888-466-3501 Monday - Friday 7am to 4pm PST, or by email via http://www.trulia.com/help/ask.