Forum Moderators: coopster
Yes, it is possible, but I don't know the specifics. You'd have to edit .htaccess or the server config files because that is done with the server and not directly with php.
Sorry for the misunderstanding. I'm a little messed up from my recent long travels and its getting pretty late.
[edit]
You should still have to make the directory using the function above, and then change your config file to point the subdomain to that directory.