different look and feel of the site based on the login user

Hi Friends,

I am having "N" number of sub sites in my site collection. For different login users I want to show the different look and feel for the sites. How can we do this. 

I heard we can use delegate control and we can achieve this. But I don't have an idea. How can we implement above scenario. If any one knows please help to resolve the issue.

Thanks,

Tiru

Tiru