need to create subdomain and mail boxes for that subdomain

Hi

I need help  on the below mentioned scenario much appreciated if I get immediately. thanks in advance.

I am created the domain ABC.com and installed the Exchange 2010  working properly. now my management want  to  create a subdomain like xyz.ABC.com. and  also they want to create the mail id like @xyz.ABC.com. Any body suggest the solutions for  this much appreciated.

Jags