You can edit "hosts" file by binding unwanted site to loopback address. But it will work for small number of sites and for console users only. If your server is used as a gateway for other clients, then you still need to install a proxy. It is not necessary to install TMG, there are other lightweight solutions.
mr podans please interduce for me lightweight solution that you are expert in that or have experience and solutions it is work
and one more question is there any way in iis avoid to customer see source my site and they can not copy my source of site?
thanks for vent your time to answer my question
I'm not familiar with lightweight proxies, but you can search them in internet. For example, http://en.wikipedia.org/wiki/Comparison_of_firewalls.
If your web site is pure HTML, then there is no way. If your web site is written in a web language (php, Java, ASP.NET), users see generated HTML code, not respective language sources.