How do you block people on your network from viewing a site?
 

How do you block people on your office network from viewing a site? Not a site you have control over, but say, for example, one wanted to block employees from looking at YouTube on office time, what is the methodology for just blocking the site, so that temptation is removed?

Squid, Websense, some other proxy server with access control. Some routers have built-in access control that you can use.

Thank you! Links to where I could get the software options please?

Here you go:

http://www.squid-cache.org/
http://www.websense.com

As a note, these aren't the easiest solutions so they would be overkill if all you want to do is block one site. What kind of router do you have?

yeah, squid cache fits just perfect.
but if you dont got much experience with networking/server admin, it's going to be a hard task.