Yes WPMU is what you need. Regular Wordpress 3.0 or higher now gives you the ability to create multiple sites WPMU style.
Yes, wordpress 3 gives you the ability to do that. Though you need to enable multisite after you've installed WP 3 on your hosting account.Just to make sure
i can create those kind of site:
subdomain.domain.com
subdomain2.domain.com
subdomain3.domain.com
if i install wordpress 3
Or if he has his own server:That is not enough. You should go to your hosting account reps so that they can setup a wildcard domain for you. Without that, you cannot use WP subdomain future automatically.
Thanks for making it exact. Actually, yours and mine should be combined for the full answer.Or if he has his own server:
Edit ServerAlias for your domain in your httpd.conf file by adding a * in front of your domain name. example: *.yourdomain.com