iptables help

["Ashley M. Kirchner" <ashley@pcraft.com>]

    I need some help adding a few blocking rules (*) to an iptables 
script that I once inherited, and grown over time.  I don't want to post 
the whole thing here because I don't need to be spamming everyone with 
it, but if there's a kind soul willing to help, I'll gladly send it 
(unless no one objects to getting the whole file.)

    (*) the basic gist is that I need to block places like hotmail.com, 
yahoo.com, and other sites from getting accessed from only two machines 
on our private network, during a specific period of time.  If we like 
the way it works, we'll add more machines/IPs to it later.