Do you want to change the address that email goes to from the "Contact Us" form? You can specify an email address for that by going to the "Site Name / URL / Contact Details" and setting the "Contact Us Email" option. It's also possible to specify alternate email addresses for one or more of the subjects listed in the "Contact Us Options" by putting the address inside curly braces in the option box, for example:
Code:
{feedback@myaddress.com} Site Feedback
{registration@myaddress.com} Registration Problem
you could also put a userid there to make the mail go to a specific user, like:
Code:
{1} Send mail to admin
(To be honest this is all according to the options help - I haven't actually tried it).