Use a different domain name then email?

Im sorry if this has been posted before, but, is it possible to change the mobile me domain name, and keep the email name the same?

for example, a iWeb site called mysightname.com

but keep the email apenaroks@me.com

I want to keep the email name I have now, but, I really dont want people to know my email address by looking at the name of the site.

Is there a way i can make the site name change?

(I'm a bit of a nob when it comes to mobile me, so, you get the point)