Yes,you can do it but either you have to owner of that domain or buy it if you are not.
Secondly you have to register MS record with the ISP of new domain name you want it.
Thirdly,you have to create a recipient policy in you exchange to send & receive mail.
The primary email address will be one at a time to send mail & you can receive email on any address.
http://www.computing.net/answers/windows-2003/exchange-mail-with-different-domain/5451.html
