[squid-users] blocking Skype

Hi
Does anyone here know how to block skype?
i already manage to block msn/icq/yahoo/irc by combining squid with
iptables
but i can't figure out how to block skype
skype use 443 port to connect if other fail
and it have random ip of it login server so it make life more difficult
to me :-\

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Nor Idzuwan Mohammad
Dr Nik & Associates SDN BHD
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