Would like to redirect all MAC users to another home page

How can I do this?

[RobbieD]

Would like to direct all MAC users to an alternative MAC home page. Does anyone know how I can do this?

[ThomasB]

In PHP $HTTP_USER_AGENT should help you. For me it shows the following:
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705; .NET CLR 1.1.4322)

The OS should also appear when using a Mac