hi ronny
to the best of my knowledge...the simple answer is no. that setup wouldnt work for your mate, as the switch in question, i believe does not have dhcp capabilities, so either the pc or the ps2 is not gonna get an IP address ( if either of them do..?)
ideally, if he can, is he able to return the switch to the seller, and buy a router instead. the linksys wrt54g is a popular choice
edit:
agatward beat me to it
and the ntl250 does not provide NAT functions