PHP : dynamic sub domains for each user using htaccess

[zz8tu]

is it possible to create dynamic sub domains for each user using htaccess. for example if there is a user with user name myusername, then add a sub domain for him like htttp://www.myusername.example.com, and when somebody load this page it should come as http://www.example.com/?user=myusername ( using htaccess )Is it possible ?Thanks