You need to setup a wildcard DNS record to catch all subdomains and send them to you web server.
Then you need to setup Apache to catch all named virtual hosts and send it to a directory.
In the directory you would set htaccess to send all requests to one script which would read the sub domain from the server variables and handle it accordingly.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…