[TriLUG] limiting Internet access with squid?

[Greg Brown]

Problem: I have a client with a small network at a resturant.  His computer
is XP Home so it can't be locked and he would like to restrict Internet
access (when he isn't there his employees are surfing the web on the office
computer, going to myspace.com, crap like that.  Can squid be set up block
all request on port 80 and force users to authenticate before passing them
along?  What I'd like is for Paul to have unrestricted access to the
Internet but his employees to be blocked from going outbound.

Is this possible with squid?  If not, do you have any other ideas?

Greg